Qur'an 2:230

فَإِن طَلَّقَهَا فَلَا تَحِلُّ لَهُۥ مِنۢ بَعْدُ حَتَّىٰ تَنكِحَ زَوْجًا غَيْرَهُۥ ۗ فَإِن طَلَّقَهَا فَلَا جُنَاحَ عَلَيْهِمَآ أَن يَتَرَاجَعَآ إِن ظَنَّآ أَن يُقِيمَا حُدُودَ ٱللَّهِ ۗ وَتِلْكَ حُدُودُ ٱللَّهِ يُبَيِّنُهَا لِقَوْمٍ يَعْلَمُونَ

“And if he has divorced her [for the third time], then she is not lawful to him afterward until [after] she marries a husband other than him. And if he [i.e., the latter husband] divorces her [or dies], there is no blame upon them [i.e., the woman and her former husband] for returning to each other if they think that they can keep [within] the limits of Allāh. These are the limits of Allāh, which He makes clear to a people who know [i.e.,understand].”

Al-Baqara 2:230 · Saheeh International