Proxy in buying and selling a commodity before receiving it

A: If you are a deputy for him in buying the commodity he wants, it will be permissible for you to take the whole price of the commodity or part of it from the person who asked you to buy it on his behalf. In this case, you have to buy it according to the specifications and requirements he determined for you. This is not a kind of selling because you do not possess the commodity at the time of deputation. It is also not a Salam sale (sale with advance payment) as the Salam is a contract for a defined commodity that should be tangible in order for it to be defined. Moreover, this commodity should be delivered at a fixed time in the future provided that the full price should be given to the seller at the time of signing the contract.But if you agree to sell him this commodity and then you buy it, (Part No. 13; Page No. 260) then this transaction will be invalid. This is because one is not permitted to sell what he does not possess. Therefore, it is not permissible for you to hold a contract with him, take any portion of the price or receive `Urbun before possessing this commodity. `Urbun sale is permissible for he who sells what he possesses. In `Urbun sale, the buyer gives the seller or his deputy a sum of money which is lesser than the price of the commodity after signing the sale contract as a guarantee for selling in order for it not to be sold to another person due to them not paying the price. If the buyer takes the commodity, `Urbun will be regarded as a portion of the price. But if he does not take the commodity, the seller will be permitted not to give the `Urbun back to the buyer. This is proved by what was done by `Umar ibn Al-Khattab (may Allah be pleased with him). Ahmad said concerning `Urbun sale: "There is no wrong in it as it was deemed lawful by Ibn `Umar (may Allah be pleased with him)." The Hadiths that reported that the Prophet (peace be upon him): "Forbade the sale involving a down payment." is a weak Hadith. It was regarded as a weak Hadith by Ahmad and others. Therefore, it can not be cited as evidence.