Reference for Chullin 281:30
גדול שלום שבין איש לאשתו שהרי אמרה תורה
- Rather, said Mar son of R'Ashi, we suppose the case where a man took up the dam in order to let it go, in which case there is no infringement of the negative precept; there is, however, a positive precept and [it might be suggested that] the positive precept [of the leper's offering] should override this positive precept.<span class="x" onmousemove="('comment',' By taking the dam he has not infringed the negative precept, since he took it for the purpose of letting it go, and even if he does not let it go it cannot be said that he has transgressed this negative precept retroactively. There now remains incumbent upon him the positive precept of letting it go, but this would be overridden if he were to retain it for the fulfilment of the positive precept of the leper's offering. The verse is therefore necessary to exclude this possibility.');"><sup>22</sup></span>