"Bitter are the sins of sentient beings,
(they) cannot be exhausted even after 1,000 kalpas;
when the bloodshed flow into rivers,
know that these are fruits of evil karma."
- Songs from Hell
I was reading LP Jarun's "The Law of Karma - Dhamma Practice" Book I the other day and came across an interesting anecdote. In the story of "The Lady with 2 Bodies", the main character Sa-ing recounted how she created evil karma through her misdeeds & how she fell into Hell to suffer for 100 yrs. She mentioned that on observance days a monk (Phra Malai) would come to teach the hell-beings. In Hell they made the hell-beings chant & pay homage to the Triple Gems. Sa-ing had never chanted before in the human world, but after being in Hell she could recite all the Kathas fluently. Phra Malai was there to teach them about Karma. He also taught that in Hell they had to chant & practice Vipassana meditation just like in the human world.
Who is this Phra Malai, teacher of the hell-beings? Legend has it that he is an Arahant from Sri Lanka, who achieved great supernormal powers through his own merits & meditation. He is also honoured as a successor to Ven Mogallana, the Buddha's disciple foremost for his supernormal attainments. The story of Phra Malai is well-known throughout Southeast Asia, especially in Thailand & Laos. In the story this pious and compassionate monk descends to Hell to give teach & comfort the suffering hell-beings there. He also learns how the hell-beings are punished according to their sins in the different hells.After returning to Earth he is presented a bunch of lotuses collected by a poor man, who wished to be freed from poverty. Phra Malai ascends to the Tavatimsa Heaven to pay homage and offer the lotuses to the Culamani Stupa, which enshrined the hair that the Bodhisatta cut off after renouncing his princely life in his father’s palace centuries ago. In this heaven, Phra Malai & Indra, King of Tavatimsa, converse on how merit is accumulated. Phra Malai eventually has the chance to meet Maitreya, the future Buddha. Maitreya gives him instructions for the people on Earth on how they may progress spiritually, make merit, and benefit further from his teaching when he eventually comes to Earth for his last existence, during which he will achieve Buddhahood. Phra Malai later returned to the human world and preached widely about Heaven & Hell, as well as Maitreya's instructions to the faithful.
The interesting thing is that even though Phra Malai had entered Parinibbana for more than 2,000 yrs ago, he continues to manifest himself in the hell realms to help the beings there. The true story of Sa-ing took place in the late 1950s. Without Phra Malai's teachings, Sa-ing would not have been able to free herself from Hell. She would probably still be suffering there till this day. Sa-ing and countless other hell-beings taught by Phra Malai throughout the centuries owe their teacher a great debt.
The deeds of Phra Malai bear striking similarities to Bodhisattva Ksitigarbha, his equivalent in Mahayana Buddhism. Perhaps they are one & the same enlightened being? Ksitigarbha is not just the Teacher of the Hell realms, but he is also the guardian of all beings in our Jambudiva world in the long time between Buddha Shakyamuni's parinirvana and Buddha Maitreya's appearance into this world. Just as Phra Malai is a Savaka Arahant, Ksitigarbha also manifests himself as a Savaka instead of a Bodhisattva to teach others. Thus he is always potrayed as a Bhikku monk rather than in Deva form like other Bodhisattvas.
Like Phra Malai, Ksitigarbha also appear in the hells on observance days to give Dana & teachings on Karma to all the hell-beings. If any of these beings seeing or hearing the Bodhisattva sincerely repent their past misdeeds, they would be liberated from their suffering through the power of the Bodhisattva's merits. Such is the great compassion shown by the Teachers of Hell.
Whether it is Phra Malai in Theravada or Ksitigarbha in Mahayana Buddhism, they teach us that no matter how much evil a person has done, such that he or she has fallen into the various hells of their own making, all it takes is a single thought of true repentance & the forsaking of past evil to be liberated. Of course, one still have to expiate one's own negative karma over time, but as long as one does not create any more new karma, the old karma will eventually be exhausted & one will be able to ride on the highway to Buddhahood without any obstacles
Source: Wayne's Dhamma Blog