What is the ruling on the promise to sell (waʿd bi-l-bayʿ) in Islam, and what is the ruling on the earnest money (tasbiqa) received when concluding a promise-to-sell contract as part of the agreed-upon amount? And is it legally obligatory to return the money to its owner if the buyer retracts from the purchase, or can the money be retained?

The promise to sell is permissible, and paying a portion of the price upon concluding the contract is called 'urbun (earnest money) sale. Scholars have differed regarding its ruling if the buyer reneges on the purchase: The majority of scholars hold that it is invalid, and the seller must return the amount. However, Imam Ahmad was of the opinion that it is permissible for the seller to keep it if they both agreed to that, and this is the more preponderant view if it was stipulated or customary.