Sunan an-Nasa'i 4478
سنن النسائي#4478SahihIt was narrated from Yazid bin 'Abdullah, from 'Abdullah bin dinar, from ibn 'Umar that he heard the Messenger of Allah say:"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
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 ZaiHasan
In-book reference: 44:30