in zavachim daf beis amud beis, ravina tell rav papa what rava said in the yeshiva on shabbos and ravina tells him that rava brought a contradiction between the first mishna in the mesechta and gitin and rava said that in our mishna it says ''all korbonos that were shechted not lishma they are kosher but lo alu labualim leshem chova'' and rava says that what is the reason that lo alu labualim leshem chova because they were shechted not lishma but if he had no intention just stam then the korbon would be kosher but by a get it says any get that was written shelo lishma is posul and even if it was written stam, so rava question is why is it different by gittin, and he answers that zevachim when you have in mind stam, lishman omdin, they stand to be offered lishmah, therefore even in the absence of specific intent is valid but isha bistama lav ligeirushin omedes, a woman, without it being specified does not stand to be divorced; therefore, the get must be written specifically for her sake, then the gemara asks from where do we know that zevachim with stam intention are kosher, and the gemara continues and says if you want to say it is from our mishna " kol hazevachim shenizbechu shelo lishman...." and since it doesn't say shelo nizbechu lishman (meaning the mishna says any korbon that was shechted not lishma, which means anything that is not that, meaning stam would be kosher) but the gemara says that can't be so because then the same thing should be by a get because it uses the same loshon there,

so my question is: that the gemara knocks off the reason rava gave so why is it trying to prove it further?

All the best,

Yehoshua

The Gemara does not push aside Rava's reason. The Gemara merely is in the middle of a process of finding a source for Rava's reasoning, which in the end it does.

All the best,

Yaakov Montrose

but rava himself says the reason and when the gemara tries to find the reason it knocks off that reason and that is my question, it knocks off rava's reason and then tries to find a reason but once it knocks off ravas reason then maybe the din doesent apply anymore?,

regards