Sayyiduna Amr bin Umayyah (may Allah be pleased with him) said that he saw the Prophet (peace and blessings be upon him) cutting meat from a shoulder of mutton that was in his hand. Then he was called to the prayer, so he (peace and blessings be upon him) put down the meat and the knife with which he had been cutting it, and he (peace and blessings be upon him) stood up and prayed, but did not perform ablution.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الصلاة / 5042