The term translated as “power” speaks of strength, force, ability, might. The term captures something intrinsic to being a “horn.” “Authority,” in contrast, refers to having the right to exercise power. The picture, then, is that these kings have a God-given right to rule (“authority”) yet use their “power” beyond the parameters God intended (i.e., to assist the beast).
13 These are of one mind, and they hand over their power and authority to the beast.