Question 2: A man who worships Allaah alone gave his beautiful daughters in marriage without receiving a Mahr (mandatory gift to a bride from her groom). He did not even receive clothing, money or anything else. Is this marriage valid?
Answer: Mahr is a prerequisite for marriage. The texts of Qur’aan and Sunnah and Ijmaa` (consensus of scholars) indicate that it is required and obligatory. Allaah (Exalted be He) says: And give to the women (whom you marry) their Mahr (obligatory bridal-money given by the husband to his wife at the time of marriage) with a good heart which means: give them their dowry out of free will according to the obligation prescribed on you by marrying them... read more here.