Ayoub al-Sakhtiyani أيوب السختياني · The Chapters on Business Transactions

the Prophet (ﷺ) forbade the deal involving earnest money .

"Do not sell fruits until they have ripened." And he forbade (both) the seller and the purchaser (to engage in such a transaction).

"Do not sell fruits until they have ripened."'

"I heard Abu Saeed Al-Khudri say: 'A Dirham for a Dirham and a Dinar for a Dinar.' So I said: 'I heard Ibn 'Abbas say something other than that.' He said: 'But I met Ibn 'Abbas and said: "Tell me about what you say concerning exchange is it something that you heard from the Messenger of Allah (ﷺ) or something that You found in the Book of Allah?" He said: "I did not find it in the Book of Allah,…

"When you have paid in advance for something, do not exchange it for something else." (Da'if)Another chain with similar wording.

"When you come to a shepherd, call him three times. If he answers (all well and good), otherwise drink (milk from the flock) without taking advantage. And when you come to a garden call the owner of the garden three times. If he answers (all well and good), otherwise eat (from the produce of the garden) without taking advantage."