Zakaria bin Abi Za'idah زكريا بن أبي زائدة خالد · Wages (Kitab Al-Ijarah)

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.

The Prophet (ﷺ) said: If anyone leaves an animal at a place of perishing and another man brings it to life, it belongs to him who brings it to life.