Musnad Ahmad 1153:940

'Abd al-Razzaq narrated to us, he said: Sufyan informed us, from Mansur, from Ibrahim, from 'Umarah ibn 'Umayr, from an aunt of his who asked 'Aishah about an orphan in her care. 'Aishah said: The Prophet, peace and blessings of Allah be upon him, said: "Indeed, the best of what a man eats is from his own earnings, and his child is from his earnings."