An Nisa, 129 Ayah
4:129
وَلَن تَسۡتَطِيعُوٓاْ أَن تَعۡدِلُواْ بَيۡنَ ٱلنِّسَآءِ وَلَوۡ حَرَصۡتُمۡۖ فَلَا تَمِيلُواْ كُلَّ ٱلۡمَيۡلِ فَتَذَرُوهَا كَٱلۡمُعَلَّقَةِۚ وَإِن تُصۡلِحُواْ وَتَتَّقُواْ فَإِنَّ ٱللَّهَ كَانَ غَفُورٗا رَّحِيمٗا ١٢٩
Wa Lan Tastaţī`ū 'An Ta`dilū Bayna An-Nisā' Wa Law Ĥaraştum ۖ Falā Tamīlū Kulla Al-Mayli Fatadharūhā Kālmu`allaqati ۚ Wa 'In Tuşliĥū Wa Tattaqū Fa'inna Al-Laha Kāna Ghafūrāan Raĥīmāan
And you will never be able to be equal [in feeling] between wives, even if you should strive [to do so]. So do not incline completely [toward one] and leave another hanging. And if you amend [your affairs] and fear Allah - then indeed, Allah is ever Forgiving and Merciful.