Quran 2.220-221
Upon the world and the Hereafter. And they question thee concerning orphans. Say: To improve their lot is best. And if ye mingle your affairs with theirs, then (they are) your brothers. Allah knoweth him who spoileth from him who improveth. Had Allah willed He could have overburdened you. Allah is Mighty, Wise. Wed not idolatresses till they believe; for lo! a believing bondwoman is better than an idolatress though she please you; and give not your daughters in marriage to idolaters till they believe, for lo! a believing slave is better than an idolater though he please you. These invite unto the Fire, and Allah inviteth unto the Garden, and unto forgiveness by His grace, and expoundeth His revelations to mankind that haply they may remember.