http://revach.net/article.php?id=3967

Section:  Avodah   Category: Chanoch L'Naar
Parshas VaEs'chanan: To Teach A Student
In the parshas of Shema it says "V'Shinantam Livanecha", you should teach your sons (VaEs'chanan 6:7).  Rashi says that this mean teaching you you talmidim, your students.  If so why does the torah write "sons", shouldn't the torah just write students without the roundabout reference?  The Shulchan Govoa brings a number of lessons from the great Roshei Yeshiva for this use of language.

Rav Yechezkel Sarna zt"l the Rosh Yeshiva of Chevron answers that we see from here that if you don't treat your talmidim like your own children then they are not even considered you talmidim.  To be considered a talmid you must treat him like a son.

Rav Yaakov Yitzchok Ruderman zt"l the Rosh Yeshiva of Ner Yisroel in Baltimore says that we learn from here that you must treat your talmid like a son in the respect that just like a son is always your son even when he grows older and no longer needs your loving care, so too a talmid always remains a talmid even after he moves on  You should never lose the Kesher with him.