Sunan an-Nasa'i, Hadith 3942 ⓘ
It was narrated from Abu Hurairah that the Prophet said: "Whoever has two wives and is inclined to favor one of them over the other, he will come on the Day of Resurrection with half of his body leaning."
أَخْبَرَنَا عَمْرُو بْنُ عَلِيٍّ، قَالَ حَدَّثَنَا عَبْدُ الرَّحْمَنِ، قَالَ حَدَّثَنَا هَمَّامٌ، عَنْ قَتَادَةَ، عَنِ النَّضْرِ بْنِ أَنَسٍ، عَنْ بَشِيرِ بْنِ نَهِيكٍ، عَنْ أَبِي هُرَيْرَةَ، عَنِ النَّبِيِّ صلى الله عليه وسلم قَالَ " مَنْ كَانَ لَهُ امْرَأَتَانِ يَمِيلُ لإِحْدَاهُمَا عَلَى الأُخْرَى جَاءَ يَوْمَ الْقِيَامَةِ أَحَدُ شِقَّيْهِ مَائِلٌ " .
also referenced under: Book 36, Hadith 4 (In-Book) & Volume 4, Book 36, Hadith 3394 (DarusSalam)