Taking the money owner's permission before lending it

A: If the reality is as you have mentioned, there is no harm in exchanging dollars for Egyptian pounds hand to hand on the spot to achieve the best interest of the money owners. Since you are just doing them a favor honestly, it is not permissible to lend anyone without the owner's permission.May Allah grant us success. May peace and blessings be upon our Prophet Muhammad, his Family, and Companions.