Muwatta Malik, Book 31, Hadith 94 (USC-MSA) ⓘ
Yahya related to me from Malik from Nafi that he heard Abdullah ibn Umar say, "If someone lends something, let the only condition be that it is repaid."
وَحَدَّثَنِي مَالِكٌ، عَنْ نَافِعٍ، أَنَّهُ سَمِعَ عَبْدَ اللَّهِ بْنَ عُمَرَ، يَقُولُ مَنْ أَسْلَفَ سَلَفًا فَلاَ يَشْتَرِطْ إِلاَّ قَضَاءَهُ .
also referenced under: Book 31, Hadith 1380 (In-Book)