What is the ruling on someone who falsely told his wife that he swore by divorce upon her, and does the divorce take effect if she swore an oath not to contact anyone and then did?

If a husband tells his wife that he swore by divorce or by making something unlawful falsely, then the divorce does not take effect, and he must repent for lying.

However, if he swore to her that she should not contact anyone, and then she did contact someone, he has broken his oath, and consequently, divorce takes effect according to the majority of scholars.

Regarding swearing by making something unlawful (haram), what matters is the intention of the swearer. If he intended divorce, then it is a divorce. If he intended ẓihār (a form of divorce by comparing one's wife to an unmarriageable kin), then it is ẓihār. If he intended an oath, or did not intend anything specific, then it is an oath for which expiation is due.

If a divorce occurs and it is not the third divorce, the husband has the right to take his wife back before her ʿiddah (waiting period) expires.

Some scholars are of the opinion that swearing by divorce or by making something unlawful with the intention of threat does not bring about divorce or ẓihār upon breaking the oath; rather, an expiation for an oath is required.