The verb impero, unlike the verb iubeo is used in a normal indirect command. A normal indirect command takes ut + subjunctive whereas iubeo takes the accusative infinitive construction as though it is an indirect statement. However, impero takes a dative noun to show which noun is the subject of the verb. If the construction were made passive, it would be impossible to keep the dative noun, meaning that a different veb, such as iubeo, must always be used.