Al-Baqarah 2:231

Wa-itha tallaqtumu annisaafabalaghna ajalahunna faamsikoohunna bimaAAroofin aw sarrihoohunnabimaAAroofin wala tumsikoohunna diraranlitaAAtadoo waman yafAAal thalika faqad thalamanafsahu wala tattakhithoo ayati Allahihuzuwan wathkuroo niAAmata Allahi AAalaykumwama anzala AAalaykum mina alkitabi walhikmatiyaAAithukum bihi wattaqoo Allaha waAAlamooanna Allaha bikulli shay-in AAaleem

And when you divorce women and they have [nearly] fulfilled their term, either retain them according to acceptable terms or release them according to acceptable terms, and do not keep them, intending harm, to transgress [against them]. And whoever does that has certainly wronged himself. And do not take the verses of Allāh in jest. And remember the favor of Allāh upon you and what has been revealed to you of the Book [i.e., the Qur’ān] and wisdom [i.e., the Prophet's sunnah] by which He instructs you. And fear Allāh and know that Allāh is Knowing of all things.

When you have divorced women, and they have approached (the end of) their waiting periods, then, either retain them with fairness or release them with fairness. Do not retain them with wrongful intent, resulting in cruelty on your part, and whoever does this, actually wrongs himself. Do not take the verses of Allah in jest, and remember the grace of Allah on you and what He has revealed to you of the Book and the wisdom, giving you good counsel thereby, and fear Allah, and be sure that Allah is the One who knows everything.