What is the ruling on buying an item on credit and then selling it for a cash price?

Question:
This is a question about murabahah (a cost-plus sale), but I mean the type they call the issue of al-dinayah.

Answer:
The issue of al-dinayah, where one buys goods on credit and sells them for a cash price to benefit from the price immediately, is permissible on the condition that the goods are in the possession of the seller when you go to him, and the goods are with him and you buy them from him on credit, then you take possession of them and move them from the seller’s location. You sell them in another place to someone other than the seller and benefit from the price. However, if you go to someone who does not have the goods and he says to you, “I will go and buy it for you at its price and record it in your name,” then he goes and takes it and gives it to you, this is not permissible. This is selling what one does not own. This is selling what one does not own.