The world is full of restaurant signs warning customers not to do things. Wear a shirt or leave. Order correctly or be yelled at. If your food sucks, don't ask for a refund because you won't get one. With all the negativity, it's refreshing to see an example of restaurant signage that celebrates customers, specifically those of a particular faith. In the case of this, we don't know much about its provenance. Someone snapped a picture somewhere, posted it to Facebook, and subsequently half the Jewish people in America started sending it bouncing through news feeds like a runaway pot-sticker.
We knew a guy in college who made a point of explaining why everything was funny. Often his habit made funny things less funny. There's no need to offer much more than the picture itself (which is quite possibly a hoax), but we will say that being partially of the tribe ourself, we appreciate the notion that the oft-angry, oft-vengeful Old Testament deity may have at some point "insisted" that his followers have dim sum on the day of that nice carpenter's birth.