A tourist walks into Duvid’s Deli and asks, “Excuse me, how do I know your pastrami is kosher?”
Duvid smiles. “Simple. Every slice comes with a guarantee.”
“Really?” says the tourist. “From which hechsher?”
Duvid points to Yankel behind the counter. “From him. If it wasn’t kosher, he’d never eat half of it before it gets to your plate.”