“Say to Aaron, ‘For the generations to come, none of your descendants who has a physical defect may approach to offer the food of his God.
17. Speak unto Aaron, saying. Priests in whom there was any notable bodily defect are here forbidden from approaching the altar. I will not curiously inquire into the defects which Moses enumerates, since the same rule is here laid down, which is afterwards applied to the sacrifices, whereof none but perfect ones were to be offered.
The priesthood being confined to one particular family, and entailed upon all the male issue of that family throughout their generations, it was very likely that some or other in after-ages that were born to the priesthood would have natural blemishes and deformities: the honour of the priesthood would not secure them from any of those calamities which are common to men.
Commenting on Leviticus 21:16-24
Speak unto Aaron, saying,.... Who being the high priest, it was incumbent on him, at least at this time, to see that the laws and rules relating to the priesthood were observed; and particularly to examine carefully who were and who were not to be admitted to serve in it: whosoever he be of thy seed in their generations; or, "a man of thy seed"...