What are the fundamental conditions for the validity of marriage in the four schools of thought?

The conditions for the validity of a marriage are summarized as follows: the woman must be eligible for marriage, and neither the man nor the woman should be in a state of ihram according to the majority of scholars (though permissible for Hanafis). The marriage must not be temporary. Compatibility (kafa'ah) is not a condition according to most scholars. Witnessing the marriage contract is the opinion of the majority, while Malikis hold that witnessing is obligatory even if it does not occur at the time of the contract.

The conditions for the enforceability of a marriage include the capacity of the contracting party (being an adult, sane, and free) and the authority to establish the contract.

The conditions for the binding nature of a marriage, according to the Hanbalis, are: kafa'ah (if the husband or the woman's guardians were deceived), and the presence of a defect in one of the spouses, such as a common defect (insanity, leprosy, vitiligo), a defect specific to the woman (vaginal occlusion, bony growth, fleshy growth), or a defect specific to the man (impotence due to castration, impotence).