Qur'ān 2:226 · Al-Baqarah (البقرة)

لِّلَّذِينَ يُؤْلُونَ مِن نِّسَآئِهِمْ تَرَبُّصُ أَرْبَعَةِ أَشْهُرٍۢ ۖ فَإِن فَآءُو فَإِنَّ ٱللَّهَ غَفُورٌۭ رَّحِيمٌۭ

For those who swear not to have sexual relations with their wives is a waiting time of four months, but if they return [to normal relations] - then indeed, Allah is Forgiving and Merciful.