the Messenger of Allah prohibited lending on the condition of a sale, or to have two conditions in one transaction, or to profit from what you do not posses. (Using translation from Nasāʾī 4629)   

«نَهَى رَسُولُ اللَّهِ ﷺ عَنْ سَلَفٍ وَبَيْعٍ وَعَنْ شَرْطَيْنِ فِي بَيْعٍ وَعَنْ رِبْحِ مَا لَمْ يُضْمَنْ»