Musannaf Ibn Abi Shayba 28:1186

'Ali ibn Mushir narrated to us, he said: Al-A'mash narrated to us, from 'Umarah, who said: Ma'dad descended into a well [or] a tree, and he said: "I do not care whether I obeyed a man in disobedience to Allah, or whether I prostrated to this tree instead of Allah."