parsha bit: B'midbar
Parshat B'midbar enumerates the heads of the tribes of Israel and then goes on to give other lineages. The torah tells us "these are the generations of Aharon and Moshe", and then proceeds to list Aharon's sons, as if they were also Moshe's sons. How can this be? Rashi explains that one who teaches torah to someone is like a father. It is from this that the talmud derives its laws about the respect owed to one's teacher. (Rashi on Num 3:1)