It's the first day of Passover and the service at the synagogue has just ended. The rabbi walks over to his shamos, Moshe, to talk religion, but before he can do so, Moshe walks away.
Following Moshe, the rabbi sees the shamos walk into a Chinese restaurant. He watches in horror as the Moshe confers with the waiter. Then, the shamos's dish arrives, topped with the delicacies of duck and shrimp.
Finally the rabbi couldn't take it any longer. "Moshe!" he cried. "Moshe, most holy shamos, what are you doing here with all of this traif food. And on Passover too!"
"I don't see what the problem is," says Moshe.
"What?" the rabbi cried, incredulous.
"Well, did you see me walk into the restaurant?"
"Yes."
"Did you see me order the food?"
"Yes."
"Did you see me eat the food"
"Yes, yes, yes!" snaps the rabbi impatiently, "Why do you think I barged in here?"
"Well," Moshe says, "I don't see where the problem is. It was all done under rabbinical supervision."