It was Hanukkah and the tiny village was in fear of not having any latkes because they had run out of flour.

Rudi, the rabbi, was called upon to help solve the problem.

He said, "don't worry, you can substitute matzo meal for the flour and the latkes will be just as delicious!"

Sheila looks to her husband and says, "Mortey...you think it'll work?" and Mortey says,

"of course! Everybody knows.........................

Rudolph, the Rab, knows grain dear!"

----
Editor's Note: A variation on the theme where the Communist is explaining the weather and the comment is "Rudolf the Red know rain, dear."