Quran 2:231 — The Heifer (Al-Baqarah)

If you divorce the women, once they fulfill their interim (three menstruations), you shall allow them to live in the same home amicably, or let them leave amicably. Do not force them to stay against their will, as a revenge. Anyone who does this wrongs his own soul. Do not take GOD's revelations in vain. Remember GOD's blessings upon you, and that He sent down to you the scripture and wisdom to enlighten you. You shall observe GOD, and know that GOD is aware of all things.

[2:230] If he divorces her (for the third time), it is unlawful for him to remarry her, unless she marries another man, then he divorces her. The first husband can then remarry her, so long as they observe GOD's laws. These are GOD's laws; He explains them for people who know.

[2:232] If you divorce the women, once they fulfill their interim, do not prevent them from remarrying their husbands, if they reconcile amicably. This shall be heeded by those among you who believe in GOD and the Last Day. This is purer for you, and more righteous. GOD knows, while you do not know.