If there be laid on him a sum of money - the ransom of his life - So it appears that, though by the law he forfeited his life, yet this might be commuted for a pecuniary mulct, at which the life of the deceased might be valued by the magistrates.

If there be laid on him a (u) sum of money, then he shall give for the ransom of his life whatsoever is laid upon him.
(u) By the next of the kindred of him that is so slain.

If there be laid on him a sum of money,.... By the decree of the judges, as Aben Ezra, or which the sanhedrim of Israel have laid upon him; if his sentence of death is commuted for a fine, with the consent of the relations of the deceased, who in such a case are willing to show mercy, and take a fine instead of the person's death; supposing it was through carelessness and negligence, and not with any ill design that he did not keep up his ox from doing damage, after he had notice:
then he shall give for the ransom of his life whatever, is laid upon him; whatever mulct or fine he is amerced with by the court, instead of the sentence of death first pronounced. Of this ransom Maimonides (q) thus writes:"the ransom is according as the judges consider what is the price (or value) of him that is slain; (i.e. according to his rank, whether a noble or common man, a free man or a servant) all is according to the estimation of him that is slain.--To whom do they give the ransom? to the heirs of the slain; and if a woman is killed, the ransom is given to the heirs of her father's (family), and not to her husband.''
(q) Hilchot Niske Mammon, c. 11. sect. 1, 2.

If there be laid on him a sum of money, &c.--Blood fines are common among the Arabs as they were once general throughout the East. This is the only case where a money compensation, instead of capital punishment, was expressly allowed in the Mosaic law.