What is the ruling on someone who, intending only to swear an oath to calm a discussion, says: "By divorce, my wife did not say such-and-such," and then remembers that his wife did say that?

If a husband swears by divorce, believing himself to be truthful and not intending to lie, then the divorce does not take effect. This is based on the statement of Ibn Taymiyyah: "The correct view is that whoever swears an oath about something he believes to be true, as if he were swearing an oath about it, and then it turns out to be otherwise, no divorce occurs upon him." Sheikh Ibn Baz agreed with this and considered it to be of the category of "laghw al-yameen" (idle or vain oath). It should be noted that the lawful oath is to swear by Allah the Almighty, whereas swearing by divorce is among the oaths of the dissolute.