"It is not righteousness that ye turn your faces Towards east or West; but it is righteousness to believe in God and the Last Day, and the Angels, and the Book, and the Messengers; to spend of your substance, out of love for Him, for your kin, for orphans, for the needy, for the wayfarer, for those who ask, and for the ransom of slaves; to be steadfast in prayer, and practice regular charity; to fulfill the contracts which ye have made; and to be firm and patient, in pain (or suffering) and adversity, and throughout all periods of panic. Such are the people of truth, the God-fearing." – Qur’an English Translation [2:177]
Ransom of slaves mean buy slaves and set them free