Buying a currency in full

A: Exchanging money must be completed at the same meeting when the contract is held. It is not permissible to receive some of it and delay another part. It was authentically reported that the Prophet (peace be upon him) said, If these classes differ, sell as you wish if payment is made hand to hand. May Allah grant us success. May peace and blessings be upon our Prophet Muhammad, his family, and Companions.