easton:
First-born, Redemption of
@ From the beginning the office of the priesthood in each family belonged to the eldest son. But when the extensive plan of sacrificial worship was introduced, requiring a company of men to be exclusively devoted to this ministry, the primitive office of the first-born was superseded by that of the Levites Numbers:3:11-13), and it was ordained that the first-born of man and of unclean animals should henceforth be redeemed (18:15). The laws concerning this redemption of the first-born of man are recorded in Exodus:13:12-15 Exodus:22:29 Exodus:34:20 ; Numbers:3:45 Numbers:8:17 Numbers:18:16 ; Leviticus:12:2-4. The first-born male of every clean animal was to be given up to the priest for sacrifice Deuteronomy:12:6; Exodus:13:12 Exodus:34:20; Numbers:18:15-17). But the first-born of unclean animals was either to be redeemed or sold and the price given to the priest Leviticus:27:11-13, 27). The first-born of an ass, if not redeemed, was to be put to death Exodus:13:13 Exodus:34:20).