"he had lived his life according to the rule"

Ten principal precepts and seventy-five minor rules for novices rules define how the members of the Sangha, the community of Buddhist monks, should conduct themselves in matters such as proper social etiquette, accepting and consuming food, handling their robes, the delivering of sermons and other miscellaneous day-to-day activities and social interactions.

A fully-fledged monk has to comply with 227 rules contained in a book called Patimokkha.

Read The Bhikkhus' Rules - A Guide for Laypeople - compiled and explained by Bhikkhu Ariyesako.