Al Mumtahanah Ayah 11

وَإِن فَاتَكُمْ شَىْءٌ مِّنْ أَزْوَٲجِكُمْ إِلَى ٱلْكُفَّارِ فَعَاقَبْتُمْ فَـَٔـاتُواْ ٱلَّذِينَ ذَهَبَتْ أَزْوَٲجُهُم مِّثْلَ مَآ أَنفَقُواْ‌ۚ وَٱتَّقُواْ ٱللَّهَ ٱلَّذِىٓ أَنتُم بِهِۦ مُؤْمِنُونَ ١١ And if any of your wives desert you to the disbelievers, and later you take spoils from them, then pay those whose wives have gone, the equivalent of whatever ?dowry? they had paid. And be mindful of Allah, in Whom you believe.