Sahih Bukhari Volume 6, Book 65, Hadith 4577

حَدَّثَنِي إِسْحَاقُ، أَخْبَرَنَا عَبْدُ اللَّهِ بْنُ نُمَيْرٍ، حَدَّثَنَا هِشَامٌ، عَنْ أَبِيهِ، عَنْ عَائِشَةَ ـ رضى الله عنها ـ فِي قَوْلِهِ تَعَالَى ‏{‏وَمَنْ كَانَ غَنِيًّا فَلْيَسْتَعْفِفْ وَمَنْ كَانَ فَقِيرًا فَلْيَأْكُلْ بِالْمَعْرُوفِ‏}‏ أَنَّهَا نَزَلَتْ فِي مَالِ الْيَتِيمِ إِذَا كَانَ فَقِيرًا، أَنَّهُ يَأْكُلُ مِنْهُ مَكَانَ قِيَامِهِ عَلَيْهِ، بِمَعْرُوفٍ‏

Narrated By 'Aisha : Regarding the statement of Allah: "And whoever amongst the guardian is rich, he should take no wages, but if he is poor, let him have for himself what is just and reasonable (according to his work). This Verse was revealed regarding the orphan's property. If the guardian is poor, he can take from the property of the orphan, what is just and reasonable according to his work and the time he spends on managing it.