Thou hast ascended in glory, O Christ our God, having gladdened Thy disciples with the promise of the Holy Spirit; and they were assured by the blessing that Thou art the Son of God, the Redeemer of the world.
- The Dismissal Hymn of the Ascension
After the exertion of Holy Week and the Feast of Feasts, Holy Pascha, everyone feels a letdown and wants to "take a vacation from church." But by so doing, we deprive ourselves of the joy of the Paschal season as it progresses naturally towards two Great Feasts which are an integral part of our participation in the Paschal Mystery, that is, Ascension Thursday and the Sunday of Pentecost.
For forty days after His Resurrection, Our Lord Jesus Christ appeared frequently to the disciples, breaking bread with them and teaching them the mysteries of the Kingdom of Heaven. Even before His Passion, however, He had told them that He must leave them, in order that the Holy Spirit, the Paraclete, could come to them: Nevertheless, I tell you the truth; It is expedient for you that I go away: for if I go not away, the Comforter will not come unto you; but if I depart, I will send Him unto you. (John 16:7) This "going away" was not the Lord's death and sleep in the tomb, for He returned immediately to be with them after the Resurrection; the words "…I go away" referred to His Ascent to the heavens, in which His bodily presence was to be taken away from the Church on earth, until the Second Coming. During this "in-between time," He is present in the Church by the grace of the Holy Spirit.
Why did Christ need to depart? Why did He not conquer the earth by divine miracles and make the Church a vehicle to take over the world and make it perfect? There are several reasons:
1. By ascending to Heaven and sitting at the right hand of the Father, He completed the glorification of the human nature He had assumed in the womb of the Virgin. As God, the Lord was always with the Father. It was not for the sake of His divine nature, but to glorify His human nature that the Son of God in His human body, with His human soul, ascended to Heaven and enthroned our human nature, in His Person, in the bosom of the Holy Trinity.
2. Our Lord's local presence on earth was not the ultimate purpose for which He came. He ascended and sent the Holy Spirit so that His disciples, having acquired the divine nature by the grace of the Holy Spirit, might acquire Christ within themselves, which is a more perfect and more sanctifying presence than His visible, bodily presence among them.
3. Christ's Kingdom is not of this world. The Church on earth is not a world-wide power structure with a visible monarchical ruler and a world capital, but is rather the mystical Body of Christ united by Faith and the Holy Mysteries, in which Christ is invisibly present by the power of the Holy Spirit. This world is corrupt and will pass away; the most virtuous organization will never make this world perfect and sinless. By remaining in the Church we escape the corruption of this world and attain Paradise, by the grace of the All-Holy Spirit.
On the Lord's Ascension
From a homily by St. Leo the Great, Pope of Rome (+461)
[By the Ascension…] our Redeemer's visible presence has passed into the Sacraments. Our faith is nobler and stronger because sight has been replaced by a doctrine whose authority is accepted by believing hearts enlightened from on high. This faith was increased by the Lord's Ascension and strengthened by the gift of the Spirit; it would remain unshaken by fetters and imprisonment, exile and hunger, fire and ravening beasts, and the most refined tortures ever devised by brutal persecutors. Throughout the world, women no less than men, tender girls as well as boys, have given their life's blood in the struggle for this faith. It is a faith that has driven out devils, healed the sick, and raised the dead.
Even the blessed Apostles, though they had been strengthened by so many miracles and instructed by so much teaching, took fright at the cruel suffering of the Lord's Passion and could not accept His Resurrection without hesitation. Yet they made such progress through His Ascension that they now found joy in what had terrified them before. They were able to fix their minds on Christ's divinity as He sat at the right hand of His Father, since what was presented to their bodily eyes no longer hindered them from turning all their attention to the realization that He had not left His Father when he came down to earth, nor had He abandoned His disciples when he ascended into heaven.
The truth is that the Son of Man was revealed as Son of God in a more perfect and transcendent way once he had entered into His Father's glory; He now began to be indescribably more present in His divinity to those from whom He was further removed in His humanity.