أَخْبَرَنَا عَمْرُو بْنُ يَزِيدَ، عَنْ بَهْزِ بْنِ أَسَدٍ، قَالَ حَدَّثَنَا شُعْبَةُ، قَالَ حَدَّثَنَا عَبْدُ اللَّهِ بْنُ دِينَارٍ، عَنِ ابْنِ عُمَرَ، قَالَ قَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم " كُلُّ بَيِّعَيْنِ فَلاَ بَيْعَ بَيْنَهُمَا حَتَّى يَتَفَرَّقَا إِلاَّ بَيْعَ الْخِيَارِ " .
It was narrated from Shu'ban who said: "Abdullah bin Dinr narrated to us, from Ibn'Umar, who said; The Messenger of Allah said; "When two people meet to engage in trade, the transaction between them is not binding until they separate, unless they have chosen to conclude the transaction." Translation Not Available
Book Ref: Sunan An Nisai Book 44 Hadith 4479
Web Ref: Sunan An Nisai Vol 5 Book 44 Hadith 4484