Third: if, during the procedure of liʿān, the husband disowns the child by declaring, “This child is not mine,” the child’s lineage to him is severed.

A husband resorts to liʿān when he actually sees his wife committing adultery yet cannot produce the required witnesses, or when powerful circumstantial evidence convinces him of her adultery—for example, if he observes a known libertine entering upon her.

The rationale for legislating liʿān in favor of the husband is that her adultery stains his honor, corrupts the sanctity of his bed, and may saddle him with another man’s child, while in most cases he cannot furnish witnesses, she will not confess, and his solitary word is not admissible against her. Nothing therefore remains but that the two of them confront one another with the gravest oaths; hence liʿān was prescribed to resolve his dilemma and lift the hardship from him.

Because he has no witness but himself, the wife is allowed to offset his oaths with an equal set of oaths, by which she averts the hadd from herself. If he balks at swearing, the penalty for slander becomes mandatory upon him; if she refuses after he has sworn, his oaths coupled with her refusal amount to decisive, unopposed evidence against her.

The eminent scholar Ibn al-Qayyim said: “This is what the evidence establishes, and it is the position of Mālik, al-Shāfiʿī, Aḥmad, and others: that she incurs the hadd if she declines to swear. This is the correct view, indicated by the Quran, and affirmed by Shaykh Ibn Taymiyyah and others.”

As for the Sunnah’s proof that liʿān is sanctioned whenever the need arises, it is the report authenticated by both al-Bukhārī and Muslim from Ibn ʿUmar: when he was asked about spouses who have performed liʿān—“Should they be separated?”