Is a man's saying to his sister, "If my wife does such-and-such, I will divorce her, or she will be divorced," considered a conditional oath, and what is the ruling if he said it ignorantly more than three times and the action occurred?

A man's statement: "I will divorce her" or "She will be divorced" is merely a promise and a threat of divorce, and divorce does not occur by it. Consequently, no divorce has occurred for this man's wife. The wife must obey her husband in what is good, and the husband should not threaten divorce. Rather, he should admonish his wife if he fears her defiance, then abandon her, then strike her with a non-injurious blow if admonition and abandonment do not work.