"If something was brought to him, the prophet would ask whether it was a gift or charity. If it was said that if was charity, he would not eat, and if it was said that it was a gift, he would stretch forth his hand." (Using translation from Nasāʾī 2613)  

كَانَ النَّبِيُّ ﷺ إِذَا أُتِيَ بِشَيْءٍ سَأَلَ عَنْهُ أَهَدِيَّةٌ أَمْ صَدَقَةٌ؟ فَإِنْ قِيلَ صَدَقَةٌ لَمْ يَأْكُلْ وَإِنْ قِيلَ هَدِيَّةٌ بَسَطَ يَدَهُ