Mishkat al-Masabih 11 Business Transactions كتاب البيوع 161

وَعَنْ جَابِرٍ قَالَ: كَانَ لِي عَلَى النَّبِيِّ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ دَيْنٌ فَقَضَانِي وَزَادَنِي. رَوَاهُ أَبُو دَاوُد

Jabir said the Prophet owed him a debt and gave him something extra when he paid it. Abu Dawud transmitted it.