It is narrated from Sayyiduna Ibn Abbas (may Allah be pleased with them both) that the Prophet (peace and blessings be upon him) came out intending to pray. On the way he passed by a cooking pot, took a bone (with meat) from it and ate it, then went on to the prayer without performing ablution.
Hadith Referenceالمعجم الكبير للطبراني / باب العين / 10695