What is the ruling on a man swearing an oath upon his wife by that which is forbidden three times, and following it with the statement that he will atone for his oath by assaulting men from the tribe of the person who wronged him?

If a man says to his wife, "You are unlawful to me," and he intends divorce, then it is a divorce. If he intends ẓihār (a pre-Islamic form of divorce by likening one's wife to one's mother), then it is ẓihār. However, if he does not intend either, then he must offer expiation for breaking an oath. This is if he breaks his oath. As for what is known as "dissolving an oath by striking ten men from the offender's tribe," this is a pre-Islamic custom that contradicts the law of Allah Almighty.