" مَنْ كَانَ لَهُ امْرَأَتَانِ يَمِيلُ لإِحْدَاهُمَا عَلَى الأُخْرَى جَاءَ يَوْمَ الْقِيَامَةِ أَحَدُ شِقَّيْهِ مَائِلٌ "
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."