An-Nisa · 4:23

23. Allah has prohibited you to marry your mothers and grandmothers, your daughters and granddaughters, your sisters and half-sisters, your aunts and great aunts, your nieces and their children, your milk-mothers who nursed you and your sisters through nursing, the mothers of your wives (whether you have consummated the marriage or not), and the daughters of your wives by someone else (who were mostly raised in your houses, and also those who were not, if you have consummated the marriage; but if you have not, then there is nothing wrong with marrying their daughters). You are also prohibited to marry those who have been married to your own sons, even if they did not consummate the marriage, and this includes the wives of your sons through milk-kinship (nursing). It is prohibited for you to marry two sisters who are related by blood or by nursing, except if this happened in the time of ignorance before Islam, in which case Allah has forgiven it. Allah is Forgiving and Compassionate to His servants who repent to Him. In the traditions of the Prophet it is also confirmed that it is prohibited to marry a woman and her aunt at the same time.