Shabbat

A curtain which was attacked by a moth was torn [round the moth hole] and resewn. R. Zutra b. Tobiah said in Rab's name: He who pulls the thread of a seam  on the Sabbath is liable to a sin-offering; and he who learns a single thing from a Magian  is worthy of death;  and he who is able to calculate the cycles  and planetary courses but does not, one may hold no conversation with him. As to magianism, Rab and Samuel [differ thereon]: one maintains that it is sorcery; the other, blasphemy. It may be proved that it is Rab who maintains that it is blasphemy. For R. Zutra b. Tobiah said in Rab's name: He who learns a single thing from a magian is worthy of death. Now should you think that it is a sorcerer, surely it is written, thou shalt not learn to do [after the abomination of those nations],  [implying], but you may learn in order to understand and instruct! This proves it. R. Simeon b. Pazzi said in the name of R. Joshua b. Levi on the authority of Bar Kappara: He who knows how to calculate the cycles and planetary courses, but does not, of him Scripture saith, but they regard not the work of the Lord, neither have they considered the operation of his hands.  R. Samuel b. Nahmani said in R. Johanan's name: How do we know that it is one's duty to calculate the cycles and planetary courses? Because it is written, for this is your wisdom and understanding in the sight of the peoples:  what wisdom and understanding is in the sight of the peoples?  Say, that it is the science of cycles and planets. CAPTURING A DEER, etc. Our Rabbis taught: He who captures a purple-fish  and crushes it is liable to one [sin-offering];  R. Judah said: He is liable to two, for R. Judah maintained: Crushing comes under the head of threshing. Said they to him: Crushing does not come under the head of threshing. Raba observed: What is the Rabbis' reason? They hold that threshing is applicable only to produce from the soil. But let him be culpable too on the score of taking life? — Said R. Johanan: This means that he crushed it when [already] dead.  Raba said: You may even explain that he crushed it whilst alive: in respect to the taking of life he is but incidentally occupied.  But Abaye and Raba both maintain: R. Simeon admits in a case of 'cut off his head but let him not die!'  Here it is different, because he is more pleased that it should be alive, so that the dye should be clearer. AND SLAUGHTERING IT. As for him who slaughters, on what score is he culpable? — Rab said: On the score of dyeing;  while Samuel said: On the score of taking life.