פירוש על עבודה זרה 152:6

'King Shapur' -- He was a gentile.

'דצה' -- He stabbed it.

'I am certain regarding this master' -- 'I know that Rav Yehudah is meticulous and will not eat a forbidden food, but I am not certain about you that you would be so meticulous.'

'What you did at night' -- It was the way of the Persians to give women to their guests, and when they sent [the women] to them the previous night, Bati received [the woman], but Rav Yehudah did not recieve [the woman].

The amoraim here explain how the two major forms of kashering are performed.How does one kasher a large pot, one that cannot be boiled inside a larger pot? One makes a rim of dough around its edges and then builds it up so that the water basically boils over. The rim will get hot water splashed on it. This is sufficient to kasher it, for just as the rim absorbed taste by having the forbidden substance splash on it, so it can emit taste in the same way.

This passage teaches how one kashers a knife. It seems that by plunging it in untilled soil, one will remove the outer layer that has been in contact with the forbidden substance.

The knife that has been kashered can only be used with cold food. Using it with hot food would cause it to emit the taste that it absorbed from the prohibited food.

In this fascinating story, the Persian King Shappur cuts some etrog slices and gives it Bati b. Tobi without kashering his knife, but kashers the knife before he gives it to Mar Yehudah. Bati is not too happy that he is not being treated like a non-Jew. The king responds that he does not know if Bati b. Tobi really is observant. And in a highly humorous end to the masekhet, the king says to him, “I remember what you did last night.” Too bad we’ll never know what naught Bati did last night. And come on, can you think of a better way to end Masechet Avodah Zarah then with a non-Jewish king kashering a knife and telling another Jew he is not observant enough?

In this fascinating story, the Persian King Shappur cuts some etrog slices and gives it Bati b. Tobi without kashering his knife, but kashers the knife before he gives it to Mar Yehudah. Bati is not too happy that he is not being treated like a non-Jew. The king responds that he does not know if Bati b. Tobi really is observant. And in a highly humorous end to the masekhet, the king says to him, “I remember what you did last night.” Too bad we’ll never know what naught Bati did last night. And come on, can you think of a better way to end Masechet Avodah Zarah then with a non-Jewish king kashering a knife and telling another Jew he is not observant enough?

That’s it folks. We finished another masekhet, another wild ride through the complicated, topsy-turvy, free-thinking, beautiful minds of Hazal, our rabbis of blessed memory. I’m hoping you found this Tractate as fascinating as I did. Discussions about how Jews can preserve their identity in a world full of people whose identity they do not share. When can Jews trust non-Jews, and when can they not? When can they use their things, and when can they not? What foods of theirs can they eat and what can they drink (not wine, that’s for sure)? It was a relevant tractate then and much of it is still relevant now. I hope you have time to review some of your learning and most importantly, I hope you continue with us onto our fifth masekhet—Kiddushin!