The Muscled Rabbi appeared in the very first cutaway in the first episode of Family Guy (not counting pilots), Death Has a Shadow.

When Meg asks Lois for collagen injections for her lips, Lois tells her that most of life's problem stem from poor self image.

The cutaway then shows "Das Gym" where Adolf Hitler is trying to lift weights. He then sees the muscled Rabbi laughing while two girls admire his muscles. Adolf Hitler then looks on angrily, implying that that was why he started the Holocaust.