Is a man's saying to his divorced wife, "You are unlawful to me as my mother is unlawful to me," considered Dhihar, and what are its consequences?

If this divorced wife was not entered upon, then she became irrevocably divorced with the first pronouncement of divorce (baynunah sughra), and the second pronouncement had no effect. If she was entered upon, the majority of scholars hold that the second pronouncement of divorce occurred. As for what was issued after the two pronouncements of divorce, it is ẓihār (a vow equating one's wife to one's mother) and not divorce. If it was before the expiry of the iddah (waiting period), then it is ẓihār for which an expiation is required before intimacy. If it was after the iddah, then it is ẓihār from a woman who is a stranger (i.e., no longer his wife), and he is not permitted to touch her before performing the expiation.