Sayyiduna Abu Rafi' (may Allah be pleased with him) narrates: The Prophet (peace and blessings be upon him) ordered me to roast a goat for him, so I roasted it. Then he (peace and blessings be upon him) said: "Hand me the foreleg." I handed him the foreleg. Then he said: "Hand me the foreleg." I handed him the foreleg. Then he said: "Hand me the foreleg." I said: O Messenger of Allah! How many forelegs does it have? He (peace and blessings be upon him) said: "Had you remained silent, you would have kept finding it for as long as I kept asking."
Hadith Referenceالمعجم الكبير للطبراني / باب الألف / 965