Quran 58:3 — The Debate (Al-Mujaadalah)

Those who estrange their wives in this manner, then reconcile thereafter, shall atone by freeing a slave before resuming their sexual relations. This is to enlighten you. GOD is Cognizant of everything you do.

[58:2] Those among you who estrange their wives (by declaring them as forbidden in sex) as their mothers know full well that they are not their mothers. Their mothers are the women who gave birth to them. Indeed, they are committing a blasphemy and a falsehood. GOD is Pardoner, Forgiver.

[58:4] If you cannot find a slave to free, you shall fast two consecutive months before resuming sexual relations. If you cannot fast, then you shall feed sixty poor people. You shall believe in GOD and His messenger. These are GOD's laws. The disbelievers have incurred a painful retribution.