All that openeth the matrix is mine. He here defines what the offering was to be, viz., that they should redeem their children as well as the unclean animals at a price; but that they should bring into the tabernacle whatsoever could be offered in sacrifice. But God would not have their own sons consecrated to Him, because He had chosen the tribe of Levi, as we shall see elsewhere; they were therefore to remain free and in their own power after a pecuniary compensation. In the same way, unclean animals might be applied to domestic purposes, viz., after God's price had been paid, since to Him they belonged, and He claimed them for Himself. But if any should not put so high a value on an ass or other unclean animal, the Law commanded that its neck should be broken; for otherwise it would have been sacrilege to reap profit from God's property, or, what is the same, to transfer to their private use what God had adjudged to Himself.

All that openeth the matrix is mine,.... Or "the womb", and therefore to be sanctified, and set apart for his use: this also was declared, and the law concerning it given, at the time of their coming out of Egypt, and here repeated; see Gill on Exodus 13:2, Exodus 13:12.