Sunan an-Nasa'i 4467
سنن النسائي#4467Sahihit was narrated from Ismail, from Nafi, that Ibn 'Umar said:"The Messenger of Allah said: 'The two parties to a transaction both have the choice so long as they have not separated, unless they have both chosen to conclude they transaction. If they have both chosen to conclude the transaction, then the transaction is binding." (Sahih)
Scholarly Authentication
We show the most cautious grade (weakest-wins) as the overall label. Individual scholars graded it as follows:
Abu GhuddahSahih
Al-AlbaniSahih
Zubair Ali ZaiIsnaad Sahih
In-book reference: 44:19