民數記 3:12 註釋：Rashi, Sforno, Chizkuni & Rav Hirsch

ואני הנה לקחתי AND I, BEHOLD I HAVE TAKEN [THE LEVITES FROM AMONG THE CHILDREN OF ISRAEL] — This means: And I — whence do “I” claim the right on them from among the children of Israel, that the Israelites should have to hire them (cf. Rashi on v. 8) for My service? It is through the firstborn — to whom I surely have a title — that I have a claim on them (the Levites) and so I take them in their (the firstborns’) stead. For originally the service (the priestly functions) was performed by the firstborn, but when they (the Israelites and among them their firstborn too) sinned by worshipping the golden calf they became disqualified, and the Levites who had not worshipped the idol were chosen in their stead (cf. Zevachim 112b).

תחת כל בכור, as a redemption.

תחת כל בכור, “in place of every firstborn;” these firstborns also had not been intended to inherit ancestral fields, ever, as they were meant to be the priests in their respective families. When the Levites were appointed to perform the tasks previously meant to be performed by the firstborn, they forfeited their claim to ancestral heritage in the Land of Israel, and the firstborns, after redemption, could then lay claim to ancestral territory as did all the non firstborn.