With Christ's return to his Father means that He could no longer be on earth in a visible way. "He was received up into heaven, and sat down at the right hand of God." ([Mark 16:19). The resurrected Savior is, in His luminous and glorious body, co-sitting with the Father in a way that Henot only through His divine naturebut also through his victorious and deified human nature, is co-equal to the Father." (Metropolitan George (Khodr) of Mt. Lebanon) This is a great mystery. His glorified body has now become a permanent and forever integral to his divinity. Christ is the God-Man forever and as such, this event could never be repeated.
From this position, He is now Savior of the World who releases the power of the Spirit upon humanity. But since we are creatures who come to know and love through the senses, a concrete earthly reality must exist to mediate his presence and saving grace which is the Church. Scripture alone is not sufficient to guarantee an encounter with the living Christ. Now the Sacraments become operative in the Church as visible, tangible expressions of Christ saving presence and grace. Every sacrament is an encounter with the living Christ who comes to us through the words-signs (e.g. baptism, confession of sins, Eucharist) that Church uses and which He implicitly or explicitly established while on earth.
Now man's encounter with Christ, who was the sacred sign of God's presence on earth, is no longer limited by his earthly humanity but through the Church in the Spirit extends to all generations and to all cosmic intelligences we may encounter on our long journey of life in the vast universe.
Associated with the Ascension is the second coming of Christ where two angels seeing the Apostles looking up to the sky said,
of Galilee, why are you standing there looking at the sky?
This Jesus who has been taken up from you into heaven will return
in the same way as you have seen him going into heaven."
The early Christians expected the imminent second coming of Christ but it did not happen. Further study of the second coming as expressed in scripture lead to the formulation of this truth in the Nicene Creed as follow:
ascended into heaven
and sits at the right hand of the father.
He will come again in glory to judge the living and the dead
and his kingdom will have no end."
Actually the Second Coming is an event that is happening now, it is an event that encompasses time and eternity. "The second coming is the impact of the paschal mystery has on the world. It is the effective reality of Christ's death and resurrection on us. The Passover of Jesus founded the Church and leads it to its end." (Francis Xavier Durrwell, C.SS.R., Christ Our Passover, Liguori, Missouri, 2004, p. 67) Each Christian has met Christ coming again in history and will face Christ judgment at death in metahistory. When the whole creation has run its course, this will be the Final Judgment and the establishment of Christ's kingdom. This event can be expressed in more evolutionary terms as follows: "The end of the world is the participation of the world in the resurrection of Jesus Christ. His Second Coming takes place at the moment of perfection of the universe, as it comes to share the reality Jesus already possesses. Then the risen Jesus Christ will be revealed as the innermost secret of the world and its history, the victory hidden at the heart of cosmic history." (Denis Edwards, Jesus and the Cosmos, Paulist Press, NY, 1991, p. 94)