G-d told Moses, "Say to the priests...say to them...."
Vayikra 21:1
The Sages teach us that the verb "to say" is repeated in this verse in order to indicate that it is priests' duty to "caution" their children regarding their priestly duties. The Hebrew word for "to caution" (להזהיר) also means "to make shine," implying that we should not be content with training our youth to observe G-d's commandments minimally and perfunctorily. Rather, we should teach them to perform the commandments in the best way possible, even going beyond the letter of the law. By imparting this enthusiasm to our children, we will enable them -- and the commandments they perform -- to sparkle and "shine."
This lesson is emphasized by the fact that the Torah conveys it in the context of its instruction to the priests. The priests' task is to help others rise spiritually and become close to G-d. So too, we should strive to educate our youth not merely to be well-versed in the Torah and punctilious in observing its commandments, but to see their study and observance as ways to draw close to G-d.
From Kehot's
Daily Wisdom #2