أَخْبَرَنَا قُتَيْبَةُ بْنُ سَعِيدٍ، قَالَ حَدَّثَنَا سُفْيَانُ، عَنْ عَبْدِ اللَّهِ بْنِ دِينَارٍ، عَنِ ابْنِ عُمَرَ، عَنِ النَّبِيِّ صلى الله عليه وسلم قَالَ " الْبَيِّعَانِ بِالْخِيَارِ مَا لَمْ يَتَفَرَّقَا أَوْ يَكُونَ بَيْعُهُمَا عَنْ خِيَارٍ " .
It was narrated from Sufyan, from 'Abdullah bin Dinar, from Ibn 'Umar, from the Prophet who said: "Two traders have the choice as long as they have not separated, or, they have chosen to conclude the transaction." Translation Not Available
Book Ref: Sunan An Nisai Book 44 Hadith 4480
Web Ref: Sunan An Nisai Vol 5 Book 44 Hadith 4485