It is narrated from Muhammad bin Sirin (may Allah have mercy on him) that Sayyiduna Umar bin al-Khattab (may Allah be pleased with him) was reciting among some people. Meanwhile he got up to relieve himself, then came back and began reciting. A man said to him: O Commander of the Believers! You have not performed ablution and you are reciting? Umar bin al-Khattab (may Allah be pleased with him) said: Who gave you this fatwa?
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الطهارة / 421