(9) باب ذِكْرِ الاِخْتِلاَفِ عَلَى نَافِعٍ فِي لَفْظِ حَدِيثِهِ
It was narrated from Yahaya, from 'Ubaidullah who said:
"Nafi narrated to me from Ibn 'Umar, tht the Messenger of Allah said: 'the two parties to a transaction both have the choice so long as they have not separated, or they have chosen." (Sahih )
Reference: Sunan an-Nasa'i 4466
In-book reference: Book 44, Hadith 18
English translation: Vol. 5, Book 44, Hadith 4471