Mark 10:20

The man’s superficial understanding of God’s standards became apparent in his claim that he had kept all those commandments from his youth up. He regarded obedience simply as external conformity without internal purity (cf. Philippians 3:6). This was the natural implication and consequence of the Pharisees’ teaching. At age 12, a Jewish boy became a "son of the covenant" (Heb. bar miswah, from which comes Bar Mitzvah). The Jews regarded themselves as responsible for their obedience to the Law from that age on. [Note: Mishnah Berachoth 2:2.] It is probably from this time that the man meant he had observed the law.