Two bags

Mr. Goldfarb was walking down the street. In each arm he carried a bag. He ran into Mr. Klein. Mr. Klein asked, "What are those bags for?" "I'm collecting for Israel", said Mr. Goldfarb. "You need two bags?", asked Mr. Klein. "I've got a system, said Mr. Goldfarb. It's fantastic. I go into the men's room. I pull out a knife and hold it up. Then I say, 'Give for Israel or get a circumcision.' It works. I have forty thousand dollars in this bag. "What do you have in the other bag?", inquired Mr. Klein. "Oh, well, not everybody gives."