Albert Barnes Commentary Exodus 21:22-25

"And if men strive together, and hurt a woman with child, so that her fruit depart, and yet no harm follow; he shall be surely fined, according as the woman`s husband shall lay upon him; and he shall pay as the judges determine. But if any harm follow, then thou shalt give life for life, eye for eye, tooth for tooth, hand for hand, foot for foot, burning for burning, wound for wound, stripe for stripe." — Exodus 21:22-25 (ASV)

The rule would seem to refer to a case in which a man's wife interfered in a quarrel. This law, “the jus talionis,” is repeated elsewhere in substance; compare the marginal references and Genesis 9:6. It has its root in a simple conception of justice and is found in the laws of many ancient nations. It serves in this place as a maxim for the magistrate in awarding the amount of compensation to be paid for the infliction of personal injury.

The sum was to be, as nearly as possible, the worth in money of the power lost by the injured person. Our Lord quotes Exodus 21:24 as representing the form of the law, in order to illustrate the distinction between the letter and the spirit (Matthew 5:38). The tendency of the teaching of the Scribes and Pharisees was to confound the obligations of conscience with the external requirements of the law. The law, in its place, was still to be holy and just and good (Romans 7:12), but its direct purpose was to protect the community, not to guide the heart of the believer, who was not to exact eye for eye, tooth for tooth, but to love his enemies, and to forgive all injuries.