"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."  

عَنِ النَّبِيِّ ﷺ قَالَ مَنْ كَانَ لَهُ امْرَأَتَانِ يَمِيلُ لإِحْدَاهُمَا عَلَى الأُخْرَى جَاءَ يَوْمَ الْقِيَامَةِ أَحَدُ شِقَّيْهِ مَائِلٌ  

"The Messenger of Allah used to divide his time equally among his wives then he would say: 'O Allah, this is what I have done with regard to that over which I have control, so do not blame me for that over which You have control and I do not.'" Hammad bin Zaid narrated it in Mursal form.  

كَانَ رَسُولُ اللَّهِ ﷺ يَقْسِمُ بَيْنَ نِسَائِهِ ثُمَّ يَعْدِلُ ثُمَّ يَقُولُ اللَّهُمَّ هَذَا فِعْلِي فِيمَا أَمْلِكُ فَلاَ تَلُمْنِي فِيمَا تَمْلِكُ وَلاَ أَمْلِكُ أَرْسَلَهُ حَمَّادُ بْنُ زَيْدٍ