It is narrated from Sayyiduna Ibn Abbas (may Allah be pleased with them both) that the Prophet (peace and blessings be upon him) went out for the prayer, and meat from the shoulder was brought to him (peace and blessings be upon him). He (peace and blessings be upon him) bit pieces off it with his teeth and ate, then went on to the prayer without rinsing his mouth and without purifying himself.
Hadith Referenceالمعجم الكبير للطبراني / باب العين / 10712