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