(9) باب ذِكْرِ الاِخْتِلاَفِ عَلَى نَافِعٍ فِي لَفْظِ حَدِيثِهِ
It was a narrated from Ayyub, from Nafi from Ibn 'Umar that the Messenger of Allah said:
"The Messenger of Allah said: "The two parties to a transaction both have the choice who long as they have not separated or one of them says to the other: 'Decide!"' (Sahih )
Reference: Sunan an-Nasa'i 4469
In-book reference: Book 44, Hadith 21
English translation: Vol. 5, Book 44, Hadith 4474