Maliks Muwatta Book 15, Hadith Number 2.
Section : Permission to Recite the Qur’an When Not in Wudu.
Yahya related to me from Malik from Ayyub ibn Abi Tamima as-Sakhtayani from Muhammad ibn Sirin that Umar ibn al-Khattab was with some people who were reciting Qur’an. He went to relieve himself and then came back and recited Qur’an. One of the men said to him, “Amir al muminin, are you reciting the Qur’an without being in wudu?” Umar replied, “Who gave you a verdict on this? Was it Musaylima?'”