A Father and a Master
Children & shidduchim
Rav Chisda teaches that forbearance on the part of a father toward his child may be permitted, but forbearance on the part of a master toward his talmid is not. A father may overlook a child's slight, since the bond is one of love. A talmid owes a master the full honor of his Torah, and so a master may not waive it.
Source: Ethical sayings of Rav Chisda