1. The training rule on sexual intercourse
Methunadhamma
A monk who has sexual intercourse is expelled. The introduction to the rule tells the background story to the laying down of the monastic law. The main principle applied by the Buddha was to lay down rules and procedures only when required by circumstances.
Translations
3. The training rule on killing a human being
Manussaviggaha
A monk who kills a human being is expelled. The origin narrative to this rule includes an unusual and much debated story about a number of monks who meditate on the unattractiveness of the body. As a result they end up committing suicide and asking others to kill them. The Buddha then teaches the meditation on mindfulness of breathing.
Translations
4. The training rule on falsely claiming a superhuman quality
Uttarimanussadhamma
A monk who falsely claims a profound spiritual attainment is expelled. In the origin story to this rule the Buddha declares that anyone who gets people to support him or her by lying about their spiritual attainments is the worst kind of thief.