The Catusacca Dipani
The Manual of the Four Noble Truths
Part IV - The Burden Of Dukkha In The Lower Planes
The khandha of beings in the four lower worlds burden them by four ways.
1) Sankhata dukkha: Unwholesome volitional actions cause beings to arise in the four lower worlds. There is the declaration: 'Papasmimramate mano' (The minds of beings take delight in evil actions). They perform evil actions according to their wishes and do not consider it as suffering while they can enjoy their lives according to their inclinations, and so its burden of sankhata consequences may be said to be not very heavy, but by judging the severity of the resultant effects, it may be said that its burden of sankhata consequences is very heavy indeed.
2) Santapa dukkha: As regards the beings that arise in the four lower worlds, the Buddha declared that it was not possible to explain in full how these beings are burdened by santapa, because they are numerous and it would occupy a great deal of time. They have been discussed generally in the Samvega-Vatthu.
Those who arise in hell will have their bones, nerves, flesh, hearts, lungs, brains, etc., all red-hot and tongues of fire will spring out of their skins. Thus they will remain for hundreds of thousands, billions, trillions, and decillions of years, experiencing intolerable heat. So long as their resultant effects are not exhausted they will not be free from such misery. In like manner there are myriads of beings who are arising in the various lower worlds, and who are suffering there for decillions and decillions of years.
(The Samvega-Vatthu also describes the santapa-dukkhe relating to the petas, ghosts, asuras (demons) and animals.)
3) Viparinama dukkha: In the case of viparinama at the end which is the passing away, one may arise in an infernal region for a single unwholesome volitional action; and when resultant effect comes to an end, one may pass away from there due to the burden of viparinama and be reborn in a lower region which is deeper than that of one's previous existence. One may not have the opportunity to arise in the happy higher planes even after thousands of existences.
Here the explanation given by the Sammohavionodani Commentary may be pointed out. For beings wandering in samsara the number of existences in which they live up to the principles of virtue are comparatively few. Most of the existences are in the lower worlds where beings prey upon one another.
Even if they happen to be reborn in the world of men for many a time, in one out of a hundred of such existences would they be able to encounter the Buddha-Dhamma and practise it. They would hold wrong views or be vicious people in a greater number of existences. Evil conduct in deeds, words and thought done by any being in an existence is incalculable. So, among worldly beings existing in the present life, any one being possesses myriads of evil actions done by him in the innumerable past existences that could drag him to hell.
Those beings who are destined to arise in the hells, in the peta world and in the asura world also possess myriads of old accumulated unwwholesome volitional actions; and the same is the case with those who arise in the planes of devas and Brahmas.
If a being who dies from the world of men, the deva plane or the Brahma plane happens to be reborn for a time in hell, all the unwholesome kamma done by him in his past existences will have the opportunity to play their parts. One evil kamma after another would cause him to be reborn continually in the four lower worlds and he would not have an opportunity to arise in the happy course of existence in another one thousand, ten thousand or a hundred thousand existences. A being bound to be reborn in the lower worlds by having performed a comparatively small amount of evil action, could arise there continuously for a great number of aeons due to his successive past kamma. There are decillions and decillions of such beings who become 'rooted in hell' and who have no opportunity to arise in the happy course of existence.
Here ends the brief exposition as to how the beings belonging to four lower worlds are burdened by way of way of santapa and viparinama.
This also explains how the khandha of a being in any one existence is burdened by sankhata, santapa and viparinama.