Is postponing the payment for a commodity after receiving it considered unlawful (haram) or among void sales, and is it permissible to pay a portion of the money and receive the commodity, with the remainder to be paid later?

There is no objection to delaying the payment of the price or paying part of it and deferring the remainder if this is done by agreement, for the delivery of the price at the session of the contract is not a condition for the validity of the sale.