Musannaf Ibn Abi Shayba 18:1211

Abu Bakr narrated to us, he said: Affan narrated to us, he said: Hammam narrated to us, from Qatadah, from al-Hasan, from Hayyaj ibn Imran al-Burjami, that Imran ibn Husayn and Samurah ibn Jundub said: The Messenger of Allah, may Allah bless him and grant him peace, forbade mutilation (al-muthlah).