"Should I perform ablution because of food I find declared lawful in the Book of Allah, simply because fire has touched it?"So Abu Hurairah gathered some pebbles and said, "I bear witness, by the number of these pebbles, that the Messenger of Allah ﷺ said, 'Perform ablution after eating what fire has touched.'"
أخبرنا إبراهيم بن يعقوب قال حدثنا عبد الصمد بن عبد الوارث قال حدثنا أبي عن حسين المعلم قال حدثني يحيى بن أبي كثير عن عبد الرحمن بن عمرو الأوزاعي أنه سمع المطلب بن عبد الله بن حنطب يقول
أتوضأ من طعام أجده في كتاب الله حلالا لأن النار مسته فجمع أبو هريرة حصى فقال أشهد عدد هذا الحصى أن رسول الله ﷺ قال توضئوا مما مست النار
[Sahih] Ahmad narrated it (2/529) from Abdul-Samad through this chain, but the chain is disconnected. It has corroborating narrations in Ibn Majah (no. 485), Tirmidhi, and others.Ahmad also narrated (1/366) with a sahih chain from Ibn Abbas, who said to Abu Hurairah, "It does not concern me what I perform wudu for. I testify that I saw the Messenger of Allah eat a shoulder of meat, then get up to pray without performing wudu." So each of them has an argument to stand on, and each is excused.