AN NISAA' — Ayat 20

وَإِنْ أَرَدتُّمُ اسْتِبْدَالَ زَوْجٍ مَّكَانَ زَوْجٍ وَآتَيْتُمْ إِحْدَاهُنَّ قِنطَارًا فَلاَ تَأْخُذُواْ مِنْهُ شَيْئًا أَتَأْخُذُونَهُ بُهْتَاناً وَإِثْماً مُّبِيناً

But if you want to replace one wife with another and you have given one of them a great amount [in gifts], do not take [back] from it anything. Would you take it in injustice and manifest sin?