Yizkor

A man comes into the shul to ask the rebbe for help. His wife is in labor and it is taking a long time for the baby to come out and he doesn’t know what to do. As it happens, the rebbe is not there that day but his young son is sitting next to place where the rebbe usually sits. After hearing the man’s problem, the rebbe’s son tells the man to go home and say Yizkor and then everything will be alright. Sure enough, the man goes home and davens Yizkor and then his wife gives birth shortly afterwards.
The next day he goes back to the shul and thanks the rebbe profusely for his son’s help.
After the man leaves, the rebbe turns to his son and tells him, “Shmerrill, I’m very impressed that you knew what to tell this man to do so his wife would give birth. But tell me, why did you tell him to say Yizkor?”
The son replies, “Because before we daven Yizkor we always say ‘Children go out!'”