"We captured some women on the Day of Awtas and they had husbands among their people. That was mentioned to the Messenger of Allah ﷺ so Allah revealed: '...And women already married, except those whom your right hands possess... (4:24)'"
أَصَبْنَا سَبَايَا يَوْمَ أَوْطَاسٍ لَهُنَّ أَزْوَاجٌ فِي قَوْمِهِنَّ فَذَكَرُوا ذَلِكَ لِرَسُولِ اللَّهِ ﷺ فَنَزَلَتْ (وَالْمُحْصَنَاتُ مِنَ النِّسَاءِ إِلاَّ مَا مَلَكَتْ أَيْمَانُكُمْ )