(Polygamy Discouraged*)
You can never be equitable in dealing with more than one wife, no matter how hard you try. Therefore, do not be so biased as to leave one of them hanging (neither enjoying marriage, nor left to marry someone else). If you correct this situation and maintain righteousness, God is Forgiver, Most Merciful.
وَلَن تَستَطيعوا أَن تَعدِلوا بَينَ النِّساءِ وَلَو حَرَصتُم فَلا تَميلوا كُلَّ المَيلِ فَتَذَروها كَالمُعَلَّقَةِ وَإِن تُصلِحوا وَتَتَّقوا فَإِنَّ اللَّهَ كانَ غَفورًا رَحيمًا
wa lan tastatee’ooo an ta’diloo bainan nisaaa’i wa law harastum falaa tameeloo kullal maili fatazaroohaa kalmu’al laqah; wa in tuslihoo wa tattaqoo fa innal laaha kaana Ghafoorar Raheema
*4:129 See Appendix 30, entitled “Polygamy.”