From his father who said that he saw the Prophet ﷺ making incisions (with a knife) into a piece of a lamb shoulder which he ate from, then he went to perform Salat without performing Wudu'.  

أَنَّهُ رَأَى النَّبِيَّ ﷺ احْتَزَّ مِنْ كَتِفِ شَاةٍ فَأَكَلَ مِنْهَا ثُمَّ مَضَى إِلَى الصَّلاَةِ وَلَمْ يَتَوَضَّأْ