Shaykh ʿAbd Allāh Ābā Buṭayn said: A marriage contracted with a woman who is still in her sister’s waiting period (ʿiddah), or the like, as well as taking a fifth wife while the fourth is still in her ʿiddah when the divorce was revocable, is void according to all scholars. If, however, the ʿiddah results from an irrevocable divorce, the jurists differ, although the authoritative position (al-madhhab) rules it impermissible.

3 – The ḥadith establishes that the marriages of non-Muslims—whether from the People of the Book or others—are to be deemed valid. Should they embrace Islam while still married, those unions stand and are treated exactly like Muslim marriages with respect to the obligatory dower, maintenance, equitable division of nights (qasm), marital chastity (iḥṣān), the possibility of divorce, ẓihār, īlāʾ, the attribution of lineage, the presumption of the marriage-bed, inheritance, and other legal consequences. This is the view of the majority of scholars, including the four Imams.

The Almighty said, “the wife of Pharaoh” (Q 66:11), and, “and his wife, the carrier of firewood” (Q 111:4). The very fact that the Quran attributes these women to their husbands indicates a sound marital bond.

Shaykh al-Islām explained: The meaning of the validity of such marriages is that they become lawful to enjoy once the parties accept Islam; should they fail to accept it, they will be punished for the union. Islam, then, is what confers validity on the marriage, just as it lifts the obligation to make up the acts of worship that had been incumbent upon them. While they remain in unbelief, validity simply means that they are left to what they have done. Thus the notion of “validity” in their legal system is not identical to its meaning in Muslim contracts.

Once the validity of their marriages is acknowledged, then if the wife is lawful at the time of conversion to Islam—or at the time the couple refer their case to us—such as a contract concluded during a waiting period that has now ended, or with the sister of a wife who has died, or a contract formed without a formula, guardian, or witnesses, the couple remain married.

If, however, the wife is someone whom it would be unlawful to marry in the first place at the moment of Islam or adjudication—such as a close blood-relative (maḥram), a woman whose ʿiddah has not yet expired, or a thrice-divorced woman who has not yet married another husband—then the couple must be separated, for whatever bars a marriage from being initiated bars its continuation even more forcefully.