They took captives (women) on the day of Autas who had their husbands. They were afraid (to have sexual intercourse with them) when this verse was revealed:" And women already married except those whom you right hands posses" (iv. 24)  

أَصَابُوا سَبْيًا يَوْمَ أَوْطَاسٍ لَهُنَّ أَزْوَاجٌ فَتَخَوَّفُوا فَأُنْزِلَتْ هَذِهِ الآيَةُ { وَالْمُحْصَنَاتُ مِنَ النِّسَاءِ إِلاَّ مَا مَلَكَتْ أَيْمَانُكُمْ}  

"We got some captives on the day of Awtas, and they had husbands among their peopled. They mentioned that to the Messenger of Allah, so the following was revealed: And women who are already married, except those whom your right hands posses.  

أَصَبْنَا سَبَايَا يَوْمَ أَوْطَاسٍ وَلَهُنَّ أَزْوَاجٌ فِي قَوْمِهِنَّ فَذَكَرُوا ذَلِكَ لِرَسُولِ اللَّهِ ﷺ فَنَزَلَتْ (وَالْمُحْصَنَاتُ مِنَ النِّسَاءِ إِلاَّ مَا مَلَكَتْ أَيْمَانُكُمْ )  

"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 )  

[Machine] That the companions of the Messenger of Allah ﷺ captured captives from the polytheists, so some of the companions of the Messenger of Allah ﷺ refrained from having relations with them out of respect for their wives. Therefore, the verse (And [also prohibited to you are all] married women except those your right hands possess) [Quran 4:24] was revealed.  

أَنَّ أَصْحَابَ رَسُولِ اللهِ ﷺ أَصَابُوا سَبَايَا مِنْ أَهْلِ الشِّرْكِ فَكَانَ نَاسٌ مِنْ أَصْحَابِ رَسُولِ اللهِ ﷺ كَفُّوا عَنْ غِشْيَانِهِنَّ مِنِ أَجْلِ أَزْوَاجِهِنَّ فَنَزَلَتْ {وَالْمُحْصَنَاتُ مِنَ النِّسَاءِ إِلَّا مَا مَلَكَتْ أَيْمَانُكُمْ} [النساء 24]