وَإِنْ أَرَدتُّمُ ٱسْتِبْدَالَ زَوْجٍ مَّكَانَ زَوْجٍ وَءَاتَيْتُمْ إِحْدَىٰهُنَّ قِنطَارًا فَلَا تَأْخُذُوا۟ مِنْهُ شَيْـًٔا ۚ أَتَأْخُذُونَهُۥ بُهْتَـٰنًا وَإِثْمًا مُّبِينًا Qur’an An-Nisaa' (4:20)Wain aradtumu istibdala zawjin makana zawjin waataytum ihdahunna qintaran fala takhuthoo minhu shayan atakhuthoonahu buhtanan waithman mubeenan
I.e., by falsely accusing her of immoral conduct in the hope of regaining her dower (see note [18] above).
Lit., "if you desire the exchange of a wife in place of a wife and you have given one of them a treasure (qintar), do not take away anything thereof". The allusion to the "exchange" of one wife for another is a clear indication of the Qur'anic view that a monogamous marriage is the desirable norm.
Treasure: Qintar = a Talent of gold: see iii. 14, first note.