Sunan an-Nasa'i, hadith 4473

أَخْبَرَنَا عَمْرُو بْنُ عَلِيٍّ، قَالَ حَدَّثَنَا عَبْدُ الْوَهَّابِ، قَالَ سَمِعْتُ يَحْيَى بْنَ سَعِيدٍ، يَقُولُ سَمِعْتُ نَافِعًا، يُحَدِّثُ عَنِ ابْنِ عُمَرَ، عَنْ رَسُولِ اللَّهِ صلى الله عليه وسلم ‏ "‏ إِنَّ الْمُتَبَايِعَيْنِ بِالْخِيَارِ فِي بَيْعِهِمَا مَا لَمْ يَفْتَرِقَا إِلاَّ أَنْ يَكُونَ الْبَيْعُ خِيَارًا ‏"‏ ‏.‏ قَالَ نَافِعٌ فَكَانَ عَبْدُ اللَّهِ إِذَا اشْتَرَى شَيْئًا يُعْجِبُهُ فَارَقَ صَاحِبَهُ ‏.‏

It was narrated from Yahya bin Sa 'eed who said:"I heard Nafi narrating from Ibn 'Umar, form the Messenger of Allah 'the two parties to a transaction both have the choice so long as they have not separated unless they have chosen to conclude the transaction. " Nafi said: ''When 'Abdullah bought something he like, he would leave straightaway