Qur'an 4:23

حُرِّمَتْ عَلَيْكُمْ أُمَّهَـٰتُكُمْ وَبَنَاتُكُمْ وَأَخَوَٰتُكُمْ وَعَمَّـٰتُكُمْ وَخَـٰلَـٰتُكُمْ وَبَنَاتُ ٱلْأَخِ وَبَنَاتُ ٱلْأُخْتِ وَأُمَّهَـٰتُكُمُ ٱلَّـٰتِىٓ أَرْضَعْنَكُمْ وَأَخَوَٰتُكُم مِّنَ ٱلرَّضَـٰعَةِ وَأُمَّهَـٰتُ نِسَآئِكُمْ وَرَبَـٰٓئِبُكُمُ ٱلَّـٰتِى فِى حُجُورِكُم مِّن نِّسَآئِكُمُ ٱلَّـٰتِى دَخَلْتُم بِهِنَّ فَإِن لَّمْ تَكُونُوا۟ دَخَلْتُم بِهِنَّ فَلَا جُنَاحَ عَلَيْكُمْ وَحَلَـٰٓئِلُ أَبْنَآئِكُمُ ٱلَّذِينَ مِنْ أَصْلَـٰبِكُمْ وَأَن تَجْمَعُوا۟ بَيْنَ ٱلْأُخْتَيْنِ إِلَّا مَا قَدْ سَلَفَ ۗ إِنَّ ٱللَّهَ كَانَ غَفُورًا رَّحِيمًا

Forbidden unto you are your mothers, and your daughters, and your sisters, and your father's sisters, and your mother's sisters, and your brother's daughters and your sister's daughters, and your foster-mothers, and your foster-sisters, and your mothers-in-law, and your step-daughters who are under your protection (born) of your women unto whom ye have gone in - but if ye have not gone in unto them, then it is no sin for you (to marry their daughters) - and the wives of your sons who (spring) from your own loins. And (it is forbidden unto you) that ye should have two sisters together, except what hath already happened (of that nature) in the past. Lo! Allah is ever Forgiving, Merciful.