Surah An-Nisa
وَلَن تَسْتَطِيعُوٓا۟ أَن تَعْدِلُوا۟ بَيْنَ ٱلنِّسَآءِ وَلَوْ حَرَصْتُمْ ۖ فَلَا تَمِيلُوا۟ كُلَّ ٱلْمَيْلِ فَتَذَرُوهَا كَٱلْمُعَلَّقَةِ ۚ وَإِن تُصْلِحُوا۟ وَتَتَّقُوا۟ فَإِنَّ ٱللَّهَ كَانَ غَفُورًا رَّحِيمًا
Wa lan tastaṭī‘ū an ta‘dilū bainan-nisā'i wa lau ḥaraṣtum falā tamīlū kullal-maili fa tażarūhā kal-mu‘allaqah(ti), wa in tuṣliḥū wa tattaqū fa innallāha kāna gafūrar raḥīmā(n).
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.