Musar for Leviticus 22:20

טמא טמא יקרא . He shall call out (13,45) "Unclean! Unclean!" This is an allusion to the statement by our sages (Kidushin 70a) that כל הפוסל במומו פוסל, "When someone declares someone else as unfit, this usually reflects upon himself," i.e. that he suffers from a similar imperfection. When the Torah says in 21,18: כל איש אשר בו מום לא יקרב, "any person who is blemished must not draw near (the Tabernacle to perform sacrificial service)," this is because in principle the priest is to offer himself when he offers a sacrifice on someone else's behalf.

Commandment 285 determines that blemished animals must not be offered as sacrifices. The Torah writes: כל אשר בו מום לא תקריבו, "Do not offer as a sacrifice anything blemished" (22,20).