What is the ruling concerning a wife to whom her husband said: "If we quarrel and I raise my hand to strike you, then you are unlawful to me until the Day of Judgment," and he subsequently did raise his hand to strike her, knowing that the husband, due to intense anger, did not know his intention at that time—was it divorce or merely a threat?

The preponderant view regarding the ruling on swearing to make one's wife unlawful (tahrim) is to refer to the husband's intention. If he intended divorce, then it is a divorce; if he intended dhihar, then it is dhihar. If he intended an oath, or if he did not intend anything, then it is an oath. As long as you are uncertain about your intention, divorce does not occur with uncertainty, and an expiation for an oath (kaffarat yamin (definition)) is incumbent upon you.