take a concubine1, not take her away from her home or town, or provide an increased bridal gift or maintenance, and similar stipulations. All such stipulations fall within the words of the Prophet (peace and blessings be upon him): “Indeed, the conditions most deserving of fulfillment are those by which sexual relations become lawful to you.” Agreed upon2.
2—The second type consists of invalid stipulations, as in temporary marriage, marriage contracted to make a woman lawful again for her former husband, and exchange marriage.
The Prophet (peace and blessings be upon him) initially granted a dispensation for temporary marriage3, but later prohibited it4.
He cursed the man who marries a woman in order to make her lawful again for her former husband, as well as the former husband for whom this is done5.
He also forbade exchange marriage, which is when one man gives6 his female ward in marriage to another on condition that the other give his own female ward in marriage to him, with no bridal gift between them7.
All of these are authentic hadiths.