Lessons Drawn from the Ḥadith:
1 – The default ruling is that whoever accuses a chaste person of fornication must furnish al-bayyina (conclusive proof). In cases of fornication the required proof is the testimony of four men. If he fails to produce such testimony, the ḥadd for qadhf (slanderous accusation) is applied to him: eighty lashes, as Allah says, “Those who accuse chaste women and then do not bring four witnesses—flog them with eighty lashes” (Qur’an 24:4).

2 – An exception to this general rule arises when a man accuses his own wife of fornication. He is still required to present four witnesses, but if he is unable to do so the ḥadd for qadhf is averted on the condition that he swear four times that he is truthfully accusing her, and on the fifth invoke Allah’s curse upon himself, saying, “And may the curse of Allah be upon me if I am among the liars.” These oaths stand in place of the four witnesses.

3 – This concession exists because, should a man witness such immorality from his wife, he cannot keep silent as he might in the case of a stranger. It is a disgrace and humiliation for him, a violation of his honour and a corruption of his bed. Therefore only one who is convinced of what he has seen would dare to accuse his wife, driven by intense protective jealousy; since the shame touches them both, this strengthens the credibility of his claim.

4 – The ḥadith indicates that Hilāl ibn Umayyah accused Sharīk of committing fornication with the accuser’s wife; the accusation directed at the wife was only implicit.

Scholarly Disagreement:
The scholars differed regarding a man who accuses another man of adultery with his own wife. The two Imams, Abū Ḥanīfah and Mālik, held that whoever makes such an accusation must bring proof; otherwise the ḥadd for qadhf is imposed on him, for he has slandered someone without necessity, and thus remains subject to the original ruling of the ḥadd.

Ibn al-ʿArabī said: “This is the plain meaning of the Qur’an, for Allah the Exalted has laid down the ḥadd in …"