Sunan Abi Dawud — Wages (Kitab Al-Ijarah) — Hadith No: 3504
Translation
Narrated 'Amr b. Suh'aib: On his father's authority, said that his grandfather 'Abd Allah b. 'Amr reported the Messenger of Allah (ﷺ) as saying: The proviso of a loan combined with a sale is not allowable, nor two conditions relating to one transaction, nor profit arising from something which is not in one's charge, nor selling what is not in your possession