'Abdullah bin Amr (may Allah be pleased with them both) says that the Messenger of Allah (peace and blessings of Allah be upon him) said: "A sale combined with a loan is not permissible 1, nor are two conditions in one sale permissible 2, nor is it permissible to benefit from something for which he is not liable 3, nor is it permissible to sell something which is not in your possession." Imam Tirmidhi says:
1- This hadith is Hasan Sahih,
2- The hadith of Hakim bin Hizam is Hasan (1232, 1233), and it is also narrated from him through other chains. And Ayyub Sakhtiyani and Abu Bishr narrated it from Yusuf bin Mahak, and Yusuf narrated it from Hakim bin Hizam. And 'Awf and Hisham bin Hassan narrated this hadith from Ibn Sirin, and Ibn Sirin from Hakim bin Hizam, and Hakim bin Hizam from the Prophet (peace and blessings of Allah be upon him), and this hadith (narration) is Mursal (disconnected). Ibn Sirin narrated it from Ayyub Sakhtiyani, and Ayyub from Yusuf bin Mahak, and Yusuf bin Mahak from Hakim bin Hizam in the same way.