Speak to the Kohanim, the sons of Aaron, and say to them (21:1)

"Speak… and say to them" - warn the elders to warn the youngsters

- Talmud, Yevamot 114a (cited as a biblical source for the concept of education)

Rabbi Yosef Yitzchok of Lubavitch told:

Once, when I was about six years old, my father called me to his room and told me to make the blessing on the tzitzis. I replied that I had already made the blessing earlier in the day. "Nevertheless, say the blessing," said father. I refused.

Father slapped me lightly - this was the only slap I ever received from him - and said: "When I tell you to do something, you must obey." Tearfully, I burst out: "If one must recite the blessing for G‑d, then I have already done so; and if one must recite the blessing because of yourcommand… well…"

Father replied: "One must recite the blessing for G‑d. But every father has been entrusted with the task to educate his children, and he must be obeyed."