(2) Absence of Proper Witnesses:
A marriage contracted in the absence of witnesses is invalid by Sunni law. The defect is regarded as arising from accidental circumstances, and can be remedied by subsequent confirmation in the presence of witnesses.
Under the Shia law, as observed above, the presence of witnesses is not necessary. Consequently, the question of this impediment does not arise under the Shia law.
(3) Difference of Religion:
According to the Shia law, in order to constitute a valid marriage, both the spouses must be Muslims. If either of them is a non-Muslim, the marriage is unlawful. But a Muslim male may contract a valid muta marriage with a kitabia or with a fire-worshipper.
(A Kitabia means a female who believes in Christianity or Judaism.)
However, under the Sunni law,
(i) A Muslim male can validly marry, not only a Muslim woman, but also a Kitabia. If he marries an idolatress or fire-worshipper, the marriage is not altogether void; it is merely irregular. The irregularity can be removed on the bride embracing Islam, or becoming a Kitabia.
(ii) A Muslim female can validly marry a Muslim alone.
If she marries a non-Muslim, the marriage is void.
Needless to say, a Sunni male may contract a valid marriage with a Shia female, and also vice-versa.
(4) Unlawful Conjunction:
A Muslim is forbidden to have two wives at the same time, so related to each other, that if either of them had been a male; they would have been prohibited from marrying each other, (as for instance, two sisters). This impediment is known as unlawful conjunction.
Nature of Marriage with Wife’s Sister:
It is true that the Quran does prohibit a man from marrying his wife’s sister during the wife’s lifetime; but this prohibition in the Quran has never been read as declaring the children of such a marriage to be illegitimate. No writer on Muhammadan law has suggested that in the case of an invalid marriage, as opposed to a void marriage, the children are illegetimate.
Where a Muslim marries a person contrary to law, and it is not possible, in any set of circumstances, for that union to become regular, the issues would not be legitimate. Marriage with the wife’s sister may be against the law when it is contracted, but it is capable of becoming a valid marriage on the divorce or death of the wife. The children of such a marriage are, therefore, legitimate: Hahiman Bibi v. Mahboob Bibi I.L.R. 41 Bom. 845.
However, according to the Calcutta High Court, such a marriage is void, and the issues are illegtimate. (Aziunnissa v. Karimunnisa, (1897) I.L.R. 23 Cal. 130). The Calcutta High Court’s view, however, does not appear to be correct.
(5) Woman Undergoing Iddat:
A marriage with a woman undergoing iddat of her previous marriage is not void, but irregular (fasid).