Upholding the precepts is sometimes distinguished in three levels: to uphold them without having formally undertaken them; to uphold them formally, willing to sacrifice one's own life for it; and finally, to spontaneously uphold them. The latter refers to the "arahant", who is understood to be morally incapable of violating the first four precepts. A layperson who upholds the precepts is described in the texts as a "jewel among laymen". On the other hand, the most serious violations of the precepts are the five actions of immediate retribution, which are believed to lead the perpetrator to an unavoidable rebirth in hell. These consist of injuring a Buddha, killing an "arahant", killing one's father or mother, and causing the monastic community to have a schism.