Musannaf Ibn Abi Shayba 13:2734

Abu Bakr narrated to us, he said: Abu Mu'awiyah narrated to us, from al-A'mash, from Ibrahim, from al-Aswad, from 'Aishah, she said: The Messenger of Allah (peace and blessings of Allah be upon him) said: "Indeed, the purest of what a man eats is from his own earnings, and his child is from his earnings."