Fear of Heaven and Good character traits[1]
Rabbinically, a father is required to guide his child in moral conduct and Yiras Shamayim until the child reaches twenty-four years old.[2]
[1] Hilchos Talmud Torah Chapter 1 Halacha 6 “And likewise, the father must guide him in the path of moral conduct and fear of Heaven in all his ways and behaviors, while his authority over his son remains firm—that is, until the son reaches the age of twenty‑four years. As it is stated: ‘Train a child according to his way; even when he grows old he will not depart from it’ (Proverbs 22:6). This training refers to the formative path that will shape his conduct throughout his life. Such education is to be carried out during his youth, specifically from the age of sixteen until the age of twenty‑four, for before the age of sixteen a child lacks sufficient maturity to fully accept rebuke. Excessive discipline and admonition should not be imposed too early, and beyond the age of twenty‑four there is concern that the son may rebel.”; Kiddushin 30a; Ketzos Hashulchan 65 footnote 13; 147 footnote 1; Encyclopedia Talmudit ibid p. 169; Piskeiy Teshuvos 343:1 footnote 15
[2] The reason: A father’s obligation to guide his son in moral conduct and fear of Heaven continues until age twenty‑four because these years are the critical period for shaping lifelong character. Before age sixteen, a child lacks the maturity to fully absorb rebuke, while after twenty‑four there is a risk that excessive admonition may lead to resistance or rebellion. The Torah emphasizes education during this formative window, when guidance can still be firmly received and internalized. As Proverbs teaches, proper training in youth establishes a path that endures throughout one’s life.