Amr bin Shu'ayb narrates from his father, and he from his grandfather (may Allah be pleased with them both), that the Messenger of Allah (peace and blessings be upon him) "forbade the earnest-money sale (bay' al-urban)." Ibn Wahb (may Allah have mercy on him) says that Imam Malik (may Allah have mercy on him) said to me: In our view of it, and Allah knows best, it is that a man buys a male or female slave, or hires something, then says to the one from whom he bought or hired it: I give you a dinar or a dirham, or more or less than that, on the condition that if I take the goods, or ride what I hired from you, then what I have given you is part of the price of the goods or of the hire of the animal; and if I abandon the sale or the hire, then what I have given you is yours, without anything in return.
The Shaykh (may Allah have mercy on him) said: This is how Malik bin Anas narrated this hadith in al-Muwatta, without naming the one from whom he narrated it.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب البيوع / 10874
Imam Malik (may Allah have mercy on him) narrated it from a trustworthy person, from Amr bin Shu'ayb. Abu Ahmad (Ibn Adi) said: It is said that Malik heard this hadith from Ibn Lahi'ah from Amr bin Shu'ayb, and the hadith of Ibn Lahi'ah from Amr bin Shu'ayb is well known; Qutaybah also narrated it from Ibn Lahi'ah from Amr bin Shu'ayb.
The Shaykh (may Allah have mercy on him) said: This hadith has also been narrated from al-Harith bin Abd al-Rahman bin Abi Dhubab from Amr bin Shu'ayb.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب البيوع / 10876
Likewise (through another chain) from al-Harith bin Abd al-Rahman bin Abi Dhubab.
Asim bin Abd al-Aziz al-Ashja'i is questionable (fihi nazar), Habib bin Abi Habib is da'if (weak), and Abdullah bin Amir and Ibn Lahi'ah are not used as proof; the basis of this hadith is the mursal report of Malik.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب البيوع / 10877