Related על חלה 1:8

One must not work for the food of the Gentiles or for the fodder of the dogs on the holiday. An incident is told about Shimon of Timnah who did not go to the house of study on the night of the holiday came. At the early in the morning R. Yehuda ben Baba met him. He said to him: Why didn't you come to the house of study last night? He said to him: A duty has come upon me, and I have fulfilled it. A band of Gentiles came into the city. I feared they would harm the residents. So, we slaughtered a calf and gave it to them to eat! He said to him: I should be surprised if your reward were not outweighed by your damage. Didn't they say: One must not work for the food of the Gentiles or for the fodder of the dogs on the holiday?!