Quran Al-Mujadila 58:4

Translation

And he who does not find [a slave] - then a fast for two months consecutively before they touch one another; and he who is unable - then the feeding of sixty poor persons. That is for you to believe [completely] in Allāh and His Messenger; and those are the limits [set by] Allāh. And for the disbelievers is a painful punishment.