33 : 52
لَّا يَحِلُّ لَكَ ٱلنِّسَآءُ مِنۢ بَعۡدُ وَلَآ أَن تَبَدَّلَ بِهِنَّ مِنۡ أَزۡوَٰجٖ وَلَوۡ أَعۡجَبَكَ حُسۡنُهُنَّ إِلَّا مَا مَلَكَتۡ يَمِينُكَۗ وَكَانَ ٱللَّهُ عَلَىٰ كُلِّ شَيۡءٖ رَّقِيبٗا
It is not lawful for you [O Prophet] to marry more women henceforth, nor can you replace any of them with others, even if their beauty may please you, except those bondwomen whom you own. And Allah is ever Watchful over all things.