Deeds committed out of greed or desire or craving or attachment (lobha), anger or hatred or ill-will or aversion (dosa), and delusion or ignorance (moha) are evil. According to their severity, in human world they are punished by man-made laws. Punishments in human world are mainly designed to isolate them to protect other good human beings from being victimised by them. Human cannot punish other human as they do in hell because hell's punishment is unthinkably cruel. These evil doers get their real punishment not in this world, but in hell after they die when their evil karma mature.
Why there is hell? Are man-made laws not good enough? Is human punishment not good enough?
Man-made laws are designed to serve interest of dominant group of people, they are not designed to judge equally to all human. By doing so they are committing evil deeds. Equal judgements by human to other human might not be possible due to their defilements they have. As these universes are governed by laws of karma, equal to every being, there is hell in the nature, not built by any supernatural being. They punish equally to all being as they deserve. Their karma, that is the volition arise at the time and during contemplation of committing the evil deed, is what gives effect to them. That is equally true for good deeds. There are havens where they are reborn and reap the fruits of their good karma and have very happy lives.
Who kill or give order to kill or encourage to kill or orchestrate or mastermind killing and who invent or manufacture or supply or sell killing weaponry have to kill more in hell and, when their evil karma weakens to be in hell, they might be reborn in hell of this world as lions or tigers or any other beings who survive by killing and eating other beings, thus multiplying evil karma many, many times, wandering in samsara countless existences. This cycle of life is mostly likely to be in hell, where there is no chance of doing any good to be reborn in happy places, like human or deva. That is why Buddha said in Chiggala sutra how difficult it is to get human life. It is a sheer coincidence that one obtains the human state; even more so difficult to be reborn as a human when a Buddha's dispensation exist in the universe, as it is so rare a Buddha appear in the world.
Is haven safe?
There was a story at the time of Buddha. In haven, one deva has five hundred devis. One of the deva's five hundred devis were singing and dancing in a beautiful garden in haven. Suddenly, it fell silent and the deva was wondering what happened to his devis and he found out that all devis died and went straight to hell. What evil they had done to be reborn in hell? Firstly, in haven, they mostly enjoy sensual pleasure, which does not produce any good karma. Secondly, they rarely do any good thing there that they will be reborn in a happy place again. Temptation to enjoy sensual pleasure is too strong in all six kamavacera havens. They do not torture in all hells. There are dark and very cold hells where beings sit there millions of years, hungry and crying for food. What was their bad karma? They do not have enough good karma to be reborn in a happy place or they have wrong view (micha ditthi), holding of that view in someone is causing unwholesome karma.
What is the safest?
Buddha said tahna (desire) is the root cause or condition of wandering in samsara. Purifying mind walking through eight noble path until no conditions are left to be reborn is the safest - Nibbana.
Q. What language do they speak in heavens and hells?
A. Pali, the universal language, spoken by every past Buddha and will speak by every future Buddha.
The following is from THE MAHAVASTU Vol. I Chapter 'Visits to Hell'.
Now the venerable Mahā-Maudgalyāyana often went on a visit to hell. There in the eight great hells, each with its sixteen secondary hells, he saw beings enduring thousands of different hellish torments.
Many were the torments which the venerable elder Kolita saw beings suffering in the hells as he went on his way. In the Sañjīva hell people had their feet upwards and heads downwards, whilst they were destroyed with hatchets and knives. Others, again, instigated by malevolence, assailed one another with claws on iron, and in their hands appeared sharp-sword-blades with which they rent one another. Yet they do not die as long as their evil karmas are not exhausted.
In the great hell Kālasūtra he saw beings with their limbs lashed with black wire, beaten and maimed and cut piece-meal with hatchets and saws. But their bodies, although beaten and mauled, grow again to undergo the same hideous torments. And thus they do not die, because they are upheld by karma.
In the great hell Sanghāta, too, he saw thousands of beings tormented by the mountains that are afire, ablaze, and aflame, while the rivers run blood. Yet, in spite of their continually roving over these mountains, they do die, because they are upheld by karma.
In Raurava he say many thousand beings suffering thousands of torments, being enclosed by solid masses of copper which was afire and ablaze, amid dense smoke.
In Mahā-Raurava which is afire, ablaze and aflame, he heard the loud wailing of those who were hurled into the fire. And the cries of the wailers re-echoed in the great mountains of Cakravāda¹ and Mahā -Cakravāda, where they reached the ears of men in the four great continents of Jambudvīpa, Pūrvavideha, Aparagodānīya, and Uttarakuru².
¹ The name of a whole world-system, in the centre of which is Mount Sineru, itself surrounded by seven mountain ranges.
² Each Cakravāda, of which the number is countless, consists of four great continents with these names.
In Tapana he saw several thousands experiencing extremely terrible sufferings, being ground from heel to neck by iron grinders, and undergoing thousands of other torments as well. Even so they do not die, because they are upheld by karma. In this great hell, which is afire, ablaze and aflame, many thousands are reborn and suffer agonies. In this great hell which is a hundred yojanas³ in perimeter, the thousands of flames which leap up from the eastern wall beat against the western; the thousands of flames which leap up from the western wall beat against the eastern. Leaping up from the southern wall they beat against the northern, and leaping up from the northern wall they beat against the southern. Leaping up from the ground they beat against the roof, and from the roof they beat against the ground. Those thousands of beings collapse on all sides, but they do not die yet, because they are upheld by karma.
³ A yojana is about seven miles
In the great hell Pratāpa there are mountains which are afire, ablaze and aflame. [The denizens of this hell) are driven to run over these mountains by hellish creatures armed with pikes. Such are the torments they undergo, but they do not die yet, because they are upheld by karma.
Then, released from this great hell they plunge into Kukkula. There also in Kukkula these people run about in flames, but they do not die yet, because they are upheld by karma. Released from Kukkula they plunge into Kunapa. There they are devoured by black creatures with jaws of iron. But still they do not die because they are upheld by karma.
Released from the secondary hell Kunapa they catch sight of delightful trees on the edge of a forest, and in search of relief they run thither. But there, hawks, vultures, ravens and owls with beaks of iron drive them from under the verdant tree and consume their flash. When their bones alone are left, their skin and flesh and blood grow again, and so they do not die, because they are upheld by karma.
Terrified by these birds, and deeming there was refuge where there was none, they enter the forest where the leaves are swords, and which is hell kumbha. When they have entered it, winds blow and cause the sharp sword-leaves to fall. These strike against their bodies, and on the body of none of them is there a spot which is not stabbed, not even a spot the size of the pore of a hair-root. But they do not die yet, because they are upheld by karma.
These beings, prostrate with wounds and with their bodies drenched with blood, then plunge into the river Vaitaranī, a river of hard acid water, by which their flaccid bodies are pierced.
The warders of hell raise their bodies thence with hooks of iron, and set them out in array on the fiery, blazing and flaming ground of the river bank. Then they ask them, "Ho! fellows, what is it that you want?" They reply, "Verily we are dying of hunger and parched with thirst." Then they warders of hell force open their mouths with bars of fiery, blazing and flaming iron. They forge pellets of iron and make those beings open their mouths into which they then throw these pellets of fiery, blazing and burning iron. "Eat this, fellows," say they. Then they tender them a drink of molten copper, saying, "Drink fellows." This molten metal burns their lips, their tongues, their palates, their throats, their entrails; it assails their bowls and passes on to their lower parts. But they do not die yet, because they are upheld by karma.
Thus when the elder Mahā-Maudgalyāyana had seen the beings in the eight hells undergoing their thousands of torments (Ah! what misery!) he came to the four assemblies in the Jeta Grove and recounted it all at length. "Thus," said he, "do the beings in the eight great hells and the sixteen secondary hells endure thousands of different torments. Therefore, one must strive after knowledge, win it, be enlightened, be fully enlightened, do good, and live the holy life. And in this world no sinful act must be committed."
The many thousands of devas and men were seized with wonder when they heard the elder Mahā-Maudgalyāyana speaking so. Such is a summary description of hell Now I shell go on to describe it in details. Read details...
The Enlightened One himself looked on this world and the world beyond, and the coming and going of men, on the round of passing away and coming to be. The Seer himself reflects upon and understands the peculiar fruition of acts which is bound up with the nature of man, ¹ and the place wherein they come to fruition.
Gotama, the Exalted One, the seer with clear insight into all things, has in his understanding named the eight hells, Sañjīva, Kālasūtra, Sanghāta, the two Rauravas, Mahāvici, Tapana and Pratāpana. Thus are these eight hells named.
Hard are they to traverse, being strewn with the consequences of terrible deeds. Each has its sixteen secondary hells. They have four corners and four gates. They are divided up and well laid out in squares. They are a hundred yojanas high, a hundred square.
They are encircled by a wall of iron, with a vault of iron above. The floor is of hot and glowing iron. Habitations hard to dwell in are they, being everywhere expanse of iron boards, hair-raising, fearful, terrible, and full of woe.
All the fearful hells are filled with hundreds of flames, each of which spreads its glow abroad a hundred yojanas. Here the many fearsome beings, the great sinners, burn a long time, even for hundreds of years. With scourges of iron the ruthless warders of hell mercilessly beat those who have sinned. These I shall tell of in well-ordered words. Give ear and attentively hear me as I speak.
In the Sañjīva hell beings hang with their feet up and their heads down, and are trimmed with axes and knives. Carried away by frenzy of anger they fight among themselves, using their won sharp claws of iron. Sharp knives also grow from their hands, and with them these utterly demented beings rend one another. Though their bodies collapse under the cold wind that blows on them, yet all their limbs are afire as they reap the fruit of their past deeds. Thus has the Master, the Tathāgata, understanding its true nature, called this hell Sañjīva, a bourne of evil deeds.
Released from Sañjīva they plunge into Kukkula. Foregathering there they are tortured for a long stretch of time. There, in Kukkula, they run about in flames for many a yojana, and suffer great misery. When they have out of Kunapa they catch sight of pleasant trees, and in quest of relief they make for the shelter of their verdant foliage. But there, hawks and vultures and ravens, with beaks of iron drive them from under a green tree, and devour their torn and gory limbs. And when they have been devoured until their bones alone are left, their skin and flesh and blood grow once more.
In their terror they run away, and deeming there was refuge where there was none, come all stricken to the terrible forest where the leaves are swords. When they have escaped from the sword-leafed forest, wounded, racked, and steeped in blood, they go to the river Vaitaranī. There they dive into the river's hot caustic water, which pierce all of their tortured limbs. Then Yama's myrmidons gaff them with hooks of iron, fling them on the river bank and give them pellets of iron to eat. They give them molten red copper to drink, which passes through their inwards down to their lower parts. Evil-dowers, those who follow the wrong way and do not perform the right deed, go down into these hells. Those who wholly eschew sinful deeds, those whose conduct is wholly virtuous do not pass to the bourne of ill.
Therefore the qualities of deeds are the two kinds, good and bad. Avoiding the bad, one should practise the good and fair.
In the Kālasūtra hell beings are driven from under a verdant tree and their limbs are hacked with hatchets and axes. Then plates of iron heated a long time are put round their bodies, burning and torturing them. When they have been burnt and tortured in this way, these plates are taken off, which causes the skin and flesh to come off in shreds and the blood to flow.
Then the warders of hell rend them from heel to neck, and many do they dash against one another in the hell Kālasūtra. After this they fling them into the smoking hell of terrible darkling Sanghāta, where no unscathed men are seen. There they run about in their milliards over many a yojana, assailing one another with leaden thongs. Thus has the Master, the Tathāgata, understanding its true nature named this hell Kālasūtra, a bourne of evil-doers.
From the surface of the hell Sanghāta mountains rise up on both sides. In between these mountains beings are herded in immense numbers. And these stony mountains come together through the working men's karma, and crush many beings like so many fire-brands. Blood flows in streams from their crushed bodies, and from this confused ile of crushed bodies issue rivers of pus.
Merciless creatures beat them up in iron tubs with iron-tipped pestles, even for many a hundred years. Thus has the Master, the Tathāgata, understanding its true nature, named this hell Sanghāta, a bourne of evil-doers. Large numbers are imprisoned in the hell Raurava, which is ablaze with fire, and make a terrible lamentations. When the fire is put out they become silent. When it flames up again, they resume their loud cries.
Another hell also has been called Raurava, horrible, shoreless, abysmal, and impassable. There the ruthless warders of hell with scourges in their hands mercilessly strike them, even form many a hundred years. Thus has the Master, the Tathāgata, understanding its true nature, named this hell Raurava, a bourne of evil-doers.
In the hell Tapana red-hot iron is prepared for them, and the wretched beings, burning like firebrands, cry out. Imprisoned here are many men of wicked conduct. Evil-doers who have sinned are here roasted. As soon as they are done and rendered inert many dogs, grate-bodied flesh-eaters, devour them. When they are devoured until their bones alone are left, their skin and flesh and blood grow again. Thus has the Master, the Tathāgata, understanding its true nature, named this hell Tapana, a bourne of evil-doers.
In the hell Pratāpana there are creatures armed with sharp pikes, and having jaws of iron. There is a fearful mountain, one great solid mass of fire. Here many people of sinful conduct are confined, and these evil-doers leap like fishes stranded on the sand. Thus has he Master, the Tathāgata, understanding its true nature, named this hell Pratāpana, a bourne of evil-doers.
Next, the hell Avīci, everywhere searing, evil, immense, red-hot, full of dense flames. On all sides, above, below and athwart, the hell Avici is like masses of iron heated in fire. The bodies of the denizens of this hell are like fire. They realise the stability of karma and that there is a no escape for them.
Seeing the gate open they rush to it, thinking that perhaps there is escape this way for them as they seek release. But as there sinful karma has not borne all it fruits, through the effect of this karma they do not win a way out of hell. Thus has the Master, the Tathāgata, understanding its true nature, name this hell Avīci, a bourne of evildoers.
Visit to the world of brutes
The venerable Mahā-Maudgalyāyana often went on a visit to the world of the brutes, and saw beings reborn among the brutes suffering miseries of various kinds. The venerable Kolita (the personal name of Mahā-Maudgalyāyana, which was a clan name) as he went journeying among the brutes, saw among them beings in extreme misery, who were glad to have dried or fresh grass to eat, and cold or worm water to drink.
They knew neither mother nor father, neither brother or sister, neither teacher nor teacher's pupil, neither friend nor kinsman. They devoured one another and drank one another's blood. They slew and strangled one another. From darkness they pass into darkness, from woe into woe, from evil plight into evil plight, from ruin into ruin. They suffered thousands of divers miseries, and in their brute state it was with difficulty that they survived them.
When he had seen this great wretchedness among the brutes, Mahā-Maudgalyāyana came to the Jeta Grove and described it all length to the four great assemblies. "Thus," said he, do beings reborn among the brutes endure thousands of divers woes, and it is with difficulty that in their brute state they survive. Therefore we should strive after knowledge, win it, be enlightened, be fully enlightened and live the holy life, and we should not commit any sin in this world. Thus I declare.
Visit to the world of ghosts
The venerable Mahā-Maudgalyāyana often went on a visit to the world of the ghosts. There he saw beings reborn in the ghost-world suffering thousands of divers miseries. The venerable elder Kolita as he went his way among the ghosts, say the ghosts in the ghost-world in extreme misery. Though their bodies are big, their mouths are size of a needle's eye, and their throats are constricted, so that, although they are always eating, they are never satisfied.
Moreover, through their failure to perform meritorious deeds, whereby they are utterly without reward, they are ill-favoured of complexion, aspect, smell, and form, and are vile and repulsive, naked, without clothes. When they are hungry and thirsty, they drink indiscriminately excrement, urine, phlegm, mucus, pus and blood.
As a maturing of their karma a wind blows and whispers "Here is something to drink! Here is something to drink! Here is boiled rice! Here is rice-gruel!" When they hear this whisper the ghosts go leaping across rivers and mountains, shouting, "Now will we eat, now will we feed, now will we drink." But those who have thus built up a hope, are immediately robbed of it, for they wind whispers to them, "There is none! There is none!" Hearing this the ghosts fall prostrate in despair.
A female ghost recites a verse:
For five hundred years have I heard this cry, "See, how hard it is to get aught to drink in the world of ghosts."
Another female ghost recites a verse:
For five hundred years have I heard this cry, "See, how hard it is to get boiled rice in the world of ghosts."
Another female ghost recites a verse:
For five hundred years have I heard this cry, "See, how hard it is to get rice-gruel in the world of ghosts."
Another female ghost recites a verse:
Thirsty they run to a stream, but its channel is empty. Scorched, they run to the shade, but when they come there they find blazing sunshine.
Another female ghost recites a verse:
An ill life have we spent, since, when we could, we did not give. When the means were at hand, we did not light a lamp for the self.
When Venerable Mahā-Maudgalyāyana had seen great wretchedness in the world of the ghosts, he came to the Jeta Grove, and in one discourse revealed it in detail to the great four assemblies. "Thus" said he, "do the beings reborn in the ghost-world suffer thousands of divers woes. Therefore we ought to strive after knowledge, win it, be enlightened, be fully enlightened, do the virtuous deed. live the holy life, and commit no sin in this world. Thus I declare."
When they heard the elder, several thousands of devas and men attained immortality (Nibbana).
Visit to Asuras (inferior devas considered as one of the four unhappy birth)
The venerable Mahā-Maudgalyāyana often went on a visit to the Asuras. In their citadel he saw Asuras of gigantic size, of frightful aspect and of great malevolence, beings who at death had fallen down in ruin to the world of the Asuras. The venerable elder Kolita as he went on his way among the Asuras, saw five classes of Asuras greatly tormented by their envy of the Suras (one kind of devas).
This is the burden of their thought: "We are down below, the devas are up above." Hence they are aggrieved, jealous, brimming over with rage, fury, and desperation, nor do they conceal it. Equipping a mighty force of four arms, namely, fighters on elephants, cavalry, charioteers, and infantry, they break up the ranks of the devas, namely the Karotapāni Yaksas, the Mālādhāra Yaksas, and the Sādamatta Yaksas (Yaksas are lower devas who support higher devas in their fight against Asuras).
Then when they have broken those ranks they join battle with the Trāyastrimśa Devas, but after they have betrayed their evil disposition towards the Trāyastrimśa Devas, who are meritorious and powerful, the Asuras, after the dissolution of the body at death, are reborn in woe, evil plight, ruin, in hell.
When venerable Mahā-Maudgalyāyana had seen the great misery of the Asuras, he came to the Jeta Grove, and in one discourse revealed it in detail to the great four assemblies. "Thus" said he, "do the beings in Mahāsamudra, the abode of the Asuras, suffer manifold miseries. Therefore we ought to strive after knowledge, win it, be enlightened, be fully enlightened, do the virtuous deed. live the holy life, and commit no sin in this world. Thus I declare."
When they heard the elder, several thousands of devas and men attained immortality (Nibbana).