The Resurrection and the Ascension are two separate concepts. This was known by the Gospel writers, particularly St. Luke. St. John also distinguishes the two, when Mary Magdalene meets the Risen Lord. Jesus says to her, “Stop holding [traditional: “do not cling to me”] on to me, for I have not yet ascended to the Father” (John 20:17). The Resurrection is the restoration to life of his human body, the Ascension is the glorification of Jesus, both God and man, at the right hand of the Father: “… the angels marveled at the sight of a human being more exalted than themselves. Today, the Father receives again in his bosom the one who was in him from eternity” (First sticheron at Psalm 140, Feast of Ascension).
The Ascension is the completion of the Paschal Mystery, the descent in humility, the exaltation again into glory. This serves as the model for every human life. It was necessary that in Christ the full glorification of the human nature be already fulfilled. Jesus did not continue to live among us in a historical sense, for our sanctification lies in accepting the Paschal Mystery of death and resurrection in faith, as our Lord told Thomas, “Blessed are those who have not seen and have believed. (John 20:29)” This, again, is the divine oikonomia. [Paraclete comes]. Jesus is already “King of kings and Lord of lords” (1 Timothy 6:15; Revelation 17:14, 19:16), and reigns at the right hand of the Father.
St. Athanasius gives the fundamental Christian interpretation of the Ascension, “Since, then, the Word was an image of God and was immortal, he assumed the form of a slave and underwent death in our behalf as a man in his own flesh, so that through this death he might, on our account, bring himself home to the Father. For this reason he is also said as a man to have been exalted on our account, and for our sake, so that, just as by his death we have all died in Christ, so conversely in Christ we may be exalted, roused from the dead and going up to the heavens, ‘where Christ entered as our forerunner’ (Hebrews 6:20); Against the Arians 1:37-43 in ACD (Ancient Christian Doctrine) 3, 163).