Abu Huraira reported:

Whenever the Messenger of Allah (ﷺ) was presented with food, he asked about it, If he was told that it was a gift, he ate out of that, and if he was told that it was a sadaqa he did not eat out of that.

حَدَّثَنَا عَبْدُ الرَّحْمَنِ بْنُ سَلاَّمٍ الْجُمَحِيُّ، حَدَّثَنَا الرَّبِيعُ، - يَعْنِي ابْنَ مُسْلِمٍ - عَنْ مُحَمَّدٍ، - وَهُوَ ابْنُ زِيَادٍ - عَنْ أَبِي هُرَيْرَةَ، ‏.‏ أَنَّ النَّبِيَّ صلى الله عليه وسلم كَانَ إِذَا أُتِيَ بِطَعَامٍ سَأَلَ عَنْهُ فَإِنْ قِيلَ هَدِيَّةٌ أَكَلَ مِنْهَا وَإِنْ قِيلَ صَدَقَةٌ لَمْ يَأْكُلْ مِنْهَا ‏.‏