brought to you by Kollel Iyun Hadaf of Yerushalayim
& Revach l'Neshamah - http://www.revach.net
1. If a person performs an action that will directly result in a Melachah, he is liable.
2. One is permitted to bandage Tzara'as on his body.
3. We prefer that a positive commandment not override a negative commandment.
4. It is permitted to perform a regular Bris Milah on Shabbos.
5. The Beraisa discusses certain limits for the cutting done during a Bris on Shabbos.
A BIT MORE
1. The concept of "Pesik Reshei" teaches that just as a person who cuts off the head of a live chicken in order to obtain a play thing (the chicken's head) for his child, the chicken surely will die (even though he did not intend to kill it), so, too, a person is liable for doing any action that definitely transgresses Shabbos even though he did not intend to achieve that result.
2. Even though there is a prohibition against cutting off Tzara'as, one is allowed to do normal things with that area of his skin such as bandage it or use it to carry packages. This is derived from the extra word "la'Asos" ("to do"), which teaches that one may do his work in a regular manner and not worry about cutting off the Tzara'as.
3. Reish Lakish: The rule of "Aseh Docheh Lo Ta'aseh" is stated only when the situation is such that the positive commandment must override the negative commandment. However, it is preferable if both can be fulfilled.
4. For example, he may do the Bris, Peri'ah, Metzitzah, and put on bandages and medicine.
5. While one is performing the Bris, he may cut any part of the foreskin that should be cut even if it would not render the Bris invalid if he did not cut it. However, if he already finished performing the Bris and later noticed that he did not cut some of the foreskin, he may cut only the area that invalidates the Bris.
Next Daf Index to Revach for Maseches Shabbos