Study Guide Shabbat 132 Today's daf is sponsored by Robyn Samuels for a refuah shelaymah u'mehayra for Yaakov Wolf Ben Tzipa. From where does Rabbi Eliezer derive that any preparations needed for a brit milah override Shabbat?  From where do we derive (according to all opinions) that a brit milah can be performed on Shabbat? The gemara brings seven possible answers and delves into each possibility. The gemara brings a proof from a braita for Rabbi Yochanan's opinion that it is derived from the word "on the day." Before quoting the derivation from the verse, the braita first suggests two possibilities that maybe logically one could infer that brit milah would override Shabbat or maybe the opposite can be inferred. Rava explains the logic behind each one. In the suggestion of Rava, the issue is raised regarding the hlacha that one cannot remove a leprous mark, even if it means that sacrifices can't be brought in the Temple. However, one can cut off a leprous mark in the performance of the mitzva of brit milah. From where is that law derived? Why is there a difference?