What procedure does a woman follow if she accuses her husband of adultery? Must she swear the li'an oath against herself as in Surat An-Nur, or does this apply only to a husband who accuses his wife?

The imprecation (li'an) is prescribed if the husband accuses his wife of adultery and does not produce four witnesses to avoid the penalty of slander (hadd al-qadhf) for himself, or if he wishes to disown a child from her. This is in accordance with the Almighty's saying: "And those who accuse their wives and have no witnesses except themselves - then the testimony of one of them shall be four testimonies [swearing] by Allah that he is of the truthful... (Verses)" [An-Nur/6].

However, if the wife accuses her husband of adultery and does not produce four witnesses, she is subjected to the penalty of slander, and no imprecation (li'an) takes place. This is in accordance with the Almighty's saying: "And those who accuse chaste women and then do not produce four witnesses - lash them with eighty lashes and never accept their testimony thereafter. And those are the defiantly disobedient," [An-Nur/4].

If the woman knows of her husband's adultery but has no evidence, she should advise him and instill in him the fear of Allah. If he persists in his error, she should seek a divorce or khul'.