From Nagarjuna's Treatise on the Great Perfection of Wisdom
(Dharmamitra Translation)

The person who breaks the precepts possesses an evil and fearsome mind. It is like that of a raak.sasa ghost. A person who breaks the precepts is one in whom people do not take refuge. This is analogous to a thirsty person's not going towards a dried-up well. The mind of the person who breaks the precepts is constantly beset with doubts and regrets. He is like a person who has committed transgressions of the law. He is always fearful that punishment will come his way. The person who breaks the precepts is like farmland which has been struck by a hail storm. One cannot rely on or look to it [for sustenance]. A person who breaks the precepts is like a bitter melon. Although in form it is like the sweet varieties, it cannot be eaten. A person who breaks the precepts is like a village populated by thieves. One cannot remain there. A person who breaks the precepts is like a person afflicted with a serious disease. One does not wish to grow close to him.

The person who breaks the precepts is unable to avoid suffering. It is just as with a wretchedly bad path. It is difficult to travel along it. One cannot remain together with a person who breaks the precepts. It is just as with an evil thief. It is difficult to grow close to him. A person who breaks the precepts is like a great abyss. Those who travel by avoid it. A person who breaks the precepts is difficult to dwell together with, the same as with a poisonous snake. A person who breaks the precepts cannot be approached or touched the same as with a huge conflagration. A person who breaks the precepts is like a wrecked boat. One cannot ride in it to ferry on across. A person who breaks the precepts is like food which has been vomited up. One cannot feast on it again.

When a person who breaks the precepts is present within a group of good people, it is like when a bad horse is present in a herd of good horses. A person who breaks the precepts is different from good people. It is just as when a donkey is present within a herd of cattle. When a person who breaks the precepts is present within the vigorous assembly, it is like when a weakling child is present among strong men. Although a person who breaks the precepts may appear to be like a bhik.su, he is like a corpse in the midst of a group of sleeping men. A person who breaks the precepts is like a counterfeit pearl in the midst of true pearls. A person who breaks the precepts is like an era.n.da tree in the midst of a forest of sandalwood. Although the person who breaks the precepts resembles a good person in appearance he contains no good dharmas within. Although he may shave his head, dye the robes, take up vouchers according to seniority and be referred to as a bhik.su, in reality he is not a bhik.su.

If a person who breaks the precepts dons the Dharma robes he encases his body in hot brass sheet metal. If he takes up the bowl then it is a vessel filled with molten brass. If he consumes food, this amounts to swallowing burning iron pellets and drinking molten brass. If he accepts offerings or support from people they are just the minion ghosts of hell who imprison him. If he enters a monastic dwelling (vihaara) he is entering a great hell. If he sits on a seat belonging to the members of the Sangha he is sitting down on a bed of hot iron.

Additionally, a person who breaks the precepts constantly experiences a feeling of fearfulness. Like a person with a serious illness, he is always afraid that death is about to come. He is also just like a person who has committed the five nefarious offenses. In his mind he always thinks to himself, "I am a thief who steals from the Buddha. He stays in hiding and avoids contact by staying in less-frequented places. He is just like a thief who is fearful of others. As the months and days of the year go by, he constantly feels ill-at-ease and insecure. Although a person who breaks the precepts may gain the benefit and pleasure of offerings, this pleasure is not pure. It is just as when a fool makes offerings to a corpse and adorns it. Whomsoever is wise, on hearing of this, is disgusted and does not wish to observe it. There are all sorts of examples such as these which are innumerable. The punishments endured by those who break the precepts are such as cannot be described. The cultivator should be single-minded in upholding the precepts.