that the Messenger of Allah said: "Whoever has two wives and favors one of them over the other, he will come on the Day of Resurrection with one of his sides leaning." (Using translation from Ibn Mājah 1969)
أَنَّ رَسُولَ اللهِ ﷺ قَالَ مَنْ كَانَتْ لَهُ امْرَأَتَانِ يَمِيلُ لِإِحْدَاهُمَا عَلَى الْأُخْرَى جَاءَ يَوْمَ الْقِيَامَةِ وَأَحَدُ شِقَّيْهِ سَاقِطٌ