Deuteronomy 33:9-11

[Aaron] who said of his father and mother, I do not regard them; nor did he acknowledge his brothers or openly recognize his own children. For the priests observed Your word and kept Your covenant [as to their limitations]. [The priests] shall teach Jacob Your ordinances and Israel Your law. They shall put incense before You and whole burnt offerings upon Your altar. Bless, O Lord, [Levi's] substance, and accept the work of his hands; crush the loins of his adversaries, and of those who hate him, that they arise no more.