What is the ruling on a husband who swore an oath of divorce, saying, "By divorce, you will not go," intending to prevent his wife from going, and then took her after four days?

You have misused your oath by divorce, and it falls under the jurisdiction of conditional divorce. If the condition upon which you swore occurs, divorce takes place according to the majority of scholars, contrary to Ibn Taymiyyah, who holds that divorce does not occur if the husband did not intend it, and he is obligated to offer an expiation for an oath. However, if you had a specific intention or the reason for the prohibition ceased to exist, then the oath is not broken, and nothing results from it.