A Non-Rabbinic Law Rejected by the Tannaim

The biblical law requiring the redemption of the firstborn of unclean animals appears in the Torah in two formulations. While Exodus limits the commandment to a firstborn ass, Numbers refers to an "unclean animal" in general. The Rabbis had two possible ways to reconcile the verses: (1) the ass was mentioned as an example, but the commandment actually applies to all unclean animals; (2) the commandment is restricted to the ass, which was intended in the phrase " unclean animal." While the Rabbis adopted the second alternative, Philo adopted the first, as did the Karaites. This paper examines the thesis put forward by others that traces of Philo's interpretation may be found in rabbinic literature, and that both possible explanations were debated by the Rabbis. Examination of the sources, ranging from the covenant of the Returnees of Zion to the late tannaitic period, reveals that, although the Rabbis were aware of the alternative intrepretation that the firstborn of any unclean animal must be redeemed, throughout tannaitic literature this interpretation was rejected in favor of the position that the obligation applies only to the firtborn of an ass. This essay also discusses the various explanations offered by the Rabbis, on the one hand, for the singling out of the ass, and, on the other hand, for the general formulation "unclean animal."