Shall we say that this is dependent on Tannaim? [For it was taught: If one says,] 'This be unto me as a firstling,' R. Jacob forbids it, while R. Jose permits it. Now, how is this meant? If we say, before the sprinkling of the blood: what is the reason of him who permits it? If after, on what grounds does the other forbid it? But it surely [means] ᵃᵇ