Hadith 513510
Chapter 31: Business Transactions - كتاب البيوع
وَحَدَّثَنِي عَنْ مَالِكٍ، عَنْ نَافِعٍ، أَنَّ عَبْدَ اللَّهِ بْنَ عُمَرَ، اشْتَرَى رَاحِلَةً بِأَرْبَعَةِ أَبْعِرَةٍ مَضْمُونَةٍ عَلَيْهِ يُوفِيهَا صَاحِبَهَا بِالرَّبَذَةِ .
Yahya related to me from Malik from Nafi that Abdullah ibn Umar bought a female riding-camel for four camels and he guaranteed to give them in full to the buyer at ar-Rabadha.
Reference Muwatta Malik 513510
USC-MSA web (English) reference : Book 31, Hadith 60