Sayyidah Aishah (may Allah be pleased with her) said concerning the saying of Allah Almighty, "And whoever is rich should abstain, and whoever is poor may consume what is reasonable" [Surah al-Nisa: 6], that this verse was revealed concerning the guardian of an orphan: when he is poor, he may eat from his wealth in a reasonable manner.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الوصايا / 12668
Amr bin Shu'ayb reports from his father, from his grandfather (may Allah be pleased with him), that a man came to the Messenger of Allah (peace and blessings be upon him) and said: "I am poor and have nothing, and I have an orphan (in my care)." He (peace and blessings be upon him) said: "Eat from your orphan's wealth without extravagance, without hastening, and without accumulating."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الوصايا / 12669
Al-Qasim bin Muhammad said that a man came to Abdullah bin Abbas (may Allah be pleased with him) and said: O Ibn Abbas! I have camels; I lend them out for their milk and for riding, and there is an orphan in my care who also has camels. What is lawful for me from my orphan's camels? Abdullah bin Abbas (may Allah be pleased with him) said: If you search for his stray camels, apply tar to the mangy ones, repair their drinking troughs, and water them on their turn, then drink without harming their offspring and without draining all the milk.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الوصايا / 12670