Mishkat al-Masabih 3371
Ibn ‘Abbas said:
When the words of God most high came down, “Do not come near an orphan’s property except to improve it,” (Al-Qur’an 6:152) and “Those who devour unjustly the property of orphans. . .” (Al-Qur’an 4:10) those who were in charge of an orphan went and separated their food and drink from his, and if any of the orphan’s food or drink was left over they kept it for him until he ate it or it went bad. Finding that a burden, they mentioned the matter to God’s Messenger, and God most high sent down, “And they ask you about orphans. Say, to set things right for them is good, and if you intermix with them they are your brethren” (Al-Qur’an 2:220). They then mixed their food and their drink with theirs. 

Abu Dawud and Nasa'i transmitted it.
عَنِ ابْنِ عَبَّاسٍ قَالَ: لَمَّا نَزَلَ قَوْلُهُ تَعَالَى (وَلَا تَقْرَبُوا مَالَ الْيَتِيمِ إِلَّا بِالَّتِي هِيَ أحسن)
وَقَوْلُهُ تَعَالَى: (إِنَّ الَّذِينَ يَأْكُلُونَ أَمْوَالَ الْيَتَامَى ظُلْمًا)
الْآيَةَ انْطَلَقَ مَنْ كَانَ عِنْدَهُ يَتِيمٌ فَعَزَلَ طَعَامه من طَعَامَهُ وَشَرَابَهُ مِنْ شَرَابِهِ فَإِذَا فَضَلَ مِنْ طَعَامِ الْيَتِيمِ وَشَرَابِهِ شَيْءٌ حُبِسَ لَهُ حَتَّى يَأْكُلَهُ أَوْ يَفْسُدَ فَاشْتَدَّ ذَلِكَ عَلَيْهِمْ فَذَكَرُوا ذَلِكَ لِرَسُولِ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ فَأَنْزَلَ اللَّهُ تَعَالَى: (وَيَسْأَلُونَكَ عَنِ الْيَتَامَى قُلْ: إصْلَاح لَهُم خير وَإِن تخالطوهم فإخوانكم)
فَخَلَطُوا طَعَامَهُمْ بِطَعَامِهِمْ وَشَرَابَهُمْ بِشَرَابِهِمْ. رَوَاهُ أَبُو دَاوُد وَالنَّسَائِيّ