EXOD1018 … Resh Lakish interprets God's use of the words "which you have broken" [this verse] to signify that on occasions bitulah shel Torah zehu yesoda, "Violation (or suspension) of the law constitutes its (firm) establishment." Menahot 99b. Rashi's interpretation (ad locum) makes it appear as if Resh Lakish's statement is altogether innocuous, and as if what Moses did was comparable to nothing more than temporarily turning from the study of Torah to the performance of such mizvot as attending to the burial of the dead or participating in a marriage ceremony. But what Moses did was obviously considered by the Rabbis to have been a much more serious case of "abrogation of the Torah" then Rashi leads us to think, as can be seen from the attempts made by the Rabbis to justify what he did. [Yevamot 62a].