John Gills Exposition of the Bible Commentary - Deuteronomy 15:21
And if there be any blemish therein ,.... In the firstling, as if it be "lame or blind", or have any ill blemish: thou shall not sacrifice it unto the Lord thy God ; blemishes in any beast made it unfit for sacrifices which were required; and so all peace offerings, vows, and freewill offerings, were to be free from any, Leviticus 22:19 , such were not fit for an holy sacrifice or an holy feast. read more
Matthew Henry's Complete Commentary - Deuteronomy 15:19-29
Here is, 1. A repetition of the law concerning the firstlings of their cattle, that, if they were males, they were to be sanctified to the Lord (Deut. 15:19), in remembrance of, and in thankfulness for, the sparing of the first-born of Israel, when the first-born of the Egyptians, both of man and beast, were slain by the destroying angel (Exod. 13:2, 15); on the eighth day it was to be given to God ( Exod. 22:30), and to be divided between the priest and the altar, Num. 18:17, 18. 2. An... read more