Surah An-Nisa, Verse 129

وَلَن تَسۡتَطِيعُوٓاْ أَن تَعۡدِلُواْ بَيۡنَ ٱلنِّسَآءِ وَلَوۡ حَرَصۡتُمۡۖ فَلَا تَمِيلُواْ كُلَّ ٱلۡمَيۡلِ فَتَذَرُوهَا كَٱلۡمُعَلَّقَةِۚ وَإِن تُصۡلِحُواْ وَتَتَّقُواْ فَإِنَّ ٱللَّهَ كَانَ غَفُورٗا رَّحِيمٗا١٢٩

walan tastaṭīʿū an taʿdilū bayna l-nisāi walaw ḥaraṣtum falā tamīlū kulla l-mayli fatadharūhā kal-muʿalaqati wa-in tuṣ'liḥū watattaqū fa-inna l-laha kāna ghafūran raḥīman

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 Allāh - then indeed, Allāh is ever Forgiving and Merciful.