Hadith 8:70
Anas reported God’s Messenger as saying, "When one of you makes a loan and the borrower sends him a present or provides an animal for him to ride, he must not ride the one or accept the other unless it is a practice they followed previously." Ibn Majah and Baihaqi, in Shu'ab al-iman , transmitted it.
وَعَنْ أَنَسٍ قَالَ: قَالَ رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ: «إِذَا أَقْرَضَ أَحَدُكُمْ قَرْضًا فَأَهْدَي إِلَيْهِ أَوْ حَمَلَهُ عَلَى الدَّابَّةِ فَلَا يَرْكَبْهُ وَلَا يَقْبَلْهَا إِلَّا أَنْ يَكُونَ جَرَى بَيْنَهُ وَبَيْنَهُ قَبْلَ ذَلِكَ» . رَوَاهُ ابْنُ مَاجَهْ وَالْبَيْهَقِيُّ فِي شُعَبِ الْإِيمَانِ
Original Reference: Mishkat al-Masabih 2831