Catechism of the Catholic Church

668 "Christ died and lived again, that he might be Lord both of the dead and of the living." ⁵⁴⁸ Christ's Ascension into heaven signifies his participation, in his humanity, in God's power and authority. Jesus Christ is Lord: he possesses all power in heaven and on earth. He is "far above all rule and authority and power and dominion", for the Father "has put all things under his feet." ⁵⁴⁹ Christ is Lord of the cosmos and of history. In him human history and indeed all creation are "set forth" and transcendently fulfilled. ⁵⁵⁰

669 As Lord, Christ is also head of the Church, which is his Body. ⁵⁵¹ Taken up to heaven and glorified after he had thus fully accomplished his mission, Christ dwells on earth in his Church. The redemption is the source of the authority that Christ, by virtue of the Holy Spirit, exercises over the Church. "The kingdom of Christ [is] already present in mystery", "on earth, the seed and the beginning of the kingdom". ⁵⁵²

670 Since the Ascension God's plan has entered into its fulfilment. We are already at "the last hour". ⁵⁵³ "Already the final age of the world is with us, and the renewal of the world is irrevocably under way; it is even now anticipated in a certain real way, for the Church on earth is endowed already with a sanctity that is real but imperfect." ⁵⁵⁴ Christ's kingdom already manifests its presence through the miraculous signs that attend its proclamation by the Church. ⁵⁵⁵