Umarah bin Umayr (may Allah have mercy on him) narrates from his paternal aunt that she asked Sayyidah Aishah (may Allah be pleased with her): There is an (orphan) child in my care; may I eat from his wealth? Sayyidah Aishah (may Allah be pleased with her) said that the Messenger of Allah (peace and blessings be upon him) said: "The purest thing a man eats is from his own earnings, and his child is (also) from his earnings."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب النفقات / 15743