Q: Is it permissible for other than the Prophet (peace be upon him) according to the Qur’an to marry one’s cousins, i.e. The daughters of one’s paternal, or maternal uncle or one’s paternal or maternal aunt?
Answer: The Islamic Shari`ah is characterized as being tolerant, all-inclusive and self-explanatory. It always adopts a moderate course between two extremes. It neither prohibits a Muslim from marrying the daughters of his paternal or maternal uncle, nor does it permit him to marry his sister or his niece. Allah (Exalted be He) says: O Prophet (Muhammad صلى الله عليه وسلم)! Verily, We have made lawful to you your wives, to whom you have paid their Mahr (bridal-money given by the husband to his wife at the time of marriage), and those (slaves) whom your right hand possesses – whom Allâh has given to you, and the daughters of your ‘Amm (paternal uncles) and the daughters of your ‘Ammât (paternal aunts) and the daughters of your Khâl (maternal uncles) and the daughters of your Khâlât (maternal aunts) who migrated (from Makkah) with you
Even though the Ayah is addressed to the Prophet (peace be upon him) himself, the Muslim Ummah (Community) is by means of allusion involved in the process. Basically any instruction addressed to the person of the Prophet (peace be upon him) is also taken as addressing his Ummah unless there exists circumstantial evidence that makes it peculiar to the Prophet (peace be upon him). An example of this is the case of the woman who came to the Prophet (peace be upon him) offering herself in marriage as indicated in the concluding words of the above verse. Allah (Exalted be He) says: …a privilege for you only, not for the (rest of) the believers. May Allah grant us success. May peace and blessings be upon our Prophet Muhammad, his family, and Companions.