The ruling on selling what the seller does not own and then providing it to the customer

Question:
He says: A customer comes to me wanting goods that may not be in my possession, or they may be in my possession but not in sufficient quantity for what the customer wants. So I conclude a sale with him and then provide it to him after agreeing on the price, because I know its price. Is this selling what I do not own?

Answer:
Yes. This is selling what you do not own. Hakim ibn Hizam (may Allah be pleased with him) came to the Messenger of Allah (peace and blessings be upon him). Hakim used to trade, buying and selling. He said to the Prophet (peace and blessings be upon him): Then I go and buy it from the market. He said (peace and blessings be upon him): So it is not permissible for a person to sell except what he owns at the time of the contract. For this reason, the scholars said that among the conditions for the validity of a sale is that the seller owns the item being sold, and that the buyer owns the price. Yes.