Qur'an 33:55

لَّا جُنَاحَ عَلَيْهِنَّ فِىٓ ءَابَآئِهِنَّ وَلَآ أَبْنَآئِهِنَّ وَلَآ إِخْوَٰنِهِنَّ وَلَآ أَبْنَآءِ إِخْوَٰنِهِنَّ وَلَآ أَبْنَآءِ أَخَوَٰتِهِنَّ وَلَا نِسَآئِهِنَّ وَلَا مَا مَلَكَتْ أَيْمَـٰنُهُنَّ ۗ وَٱتَّقِينَ ٱللَّهَ ۚ إِنَّ ٱللَّهَ كَانَ عَلَىٰ كُلِّ شَىْءٍ شَهِيدًا

It is no sin for them (thy wives) (to converse freely) with their fathers, or their sons, or their brothers, or their brothers' sons, or the sons of their sisters or of their own women, or their slaves. O women! Keep your duty to Allah. Lo! Allah is ever Witness over all things.