Mua'dh bin Hisham bin Aby معاذ بن هشام بن أبي عبد الله · The Book of Financial Transactions

"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 to conclude the transaction.' Or perhaps Nafi said: "Or one of them has said to the other: 'Decide! (Sahih )