كتاب المساقاة
22  
The Book of Musaqah
(22)
Chapter: It is permissible to lend animals and it is recommended to pay in full, giving something better than that which ts owed
(22)
باب مَنِ اسْتَسْلَفَ شَيْئًا فَقَضَى خَيْرًا مِنْهُ وَ ‏"‏ خَيْرُكُمْ أَحْسَنُكُمْ قَضَاءً ‏"‏ ‏‏
Sahih Muslim 1601 c

Abu Huraira (Allah be pleased with him) reported:

There came a person demanding a camel from Allah's Messenger (ﷺ). He (the Holy Prophet) said: Give him (the camel) of that age or of more mature age, and said: Best among you is one who is best in clearing off the debt.
حَدَّثَنَا مُحَمَّدُ بْنُ عَبْدِ اللَّهِ بْنِ نُمَيْرٍ، حَدَّثَنَا أَبِي، حَدَّثَنَا سُفْيَانُ، عَنْ سَلَمَةَ بْنِ كُهَيْلٍ، عَنْ أَبِي سَلَمَةَ، عَنْ أَبِي هُرَيْرَةَ، قَالَ جَاءَ رَجُلٌ يَتَقَاضَى رَسُولَ اللَّهِ صلى الله عليه وسلم بَعِيرًا فَقَالَ ‏ "‏ أَعْطُوهُ سِنًّا فَوْقَ سِنِّهِ - وَقَالَ - خَيْرُكُمْ أَحْسَنُكُمْ قَضَاءً ‏"‏ ‏.
Reference : Sahih Muslim 1601c
In-book reference : Book 22, Hadith 151
USC-MSA web (English) reference : Book 10, Hadith 3900
  (deprecated numbering scheme)