C. F. Keil and Franz Delitzsch on Exodus 21:31-32

Exo 21:31-32

The death of a son or a daughter through the goring of an ox was also to be treated in the same way; but that of a slave (man-servant or maid-servant) was to be compensated by the payment of thirty shekels of silver (i.e., probably the ordinary price for the redemption of a slave, as the redemption price of a free Israelite was fifty shekels, Lev 27:3) on the part of the owner of the ox; but the ox was to be killed in this case also. There are other ancient nations in whose law books we find laws relating to the punishment of animals for killing or wounding a man, but not one of them had a law which made the owner of the animal responsible as well, for they none of them looked upon human life in its likeness of God.