The ascension:-

1. Marks the transition between Jesus’ earthly and heavenly existence, Jn 6:62; Eph 4:10. ‘The doctrine of bodily absence is balanced in the NT by the doctrine of spiritual presence.’ (NBD)
2. Confirms our Lord’s exalted status and kingly triumph, 1 Tim 3:16; Col 3:1; Heb 1:3; 8:1; 10:12; 12:2; Eph 4:8.
3. Prepares the way for his return, Jn 14:1-14.

It establishes three facts:-

1. Christ’s personal ascendancy. Jesus went up to the place of power, pictured as a throne at the Father’s right hand. To sit on such a throne, as the Grand Vizier in the Persian court used to do, is to occupy the position of executive ruler on the monarch’s behalf. (Mt 28:18; Eph 1:20-22; 1 Cor 15:27; 1 Pet 3:22)

2. Christ’s spiritual omnipresence. In the heavenly sanctuary in heavenly Zion, (Heb 9:24; 12:22-24) Jesus is accessible to all who invoke him, (Heb 4:14) and he is powerful to help them, anywhere in the world. (Heb 4:16; 7:25; 13:6-8)

3. Christ’s heavenly ministry. The reigning Lord intercedes for his people. (Rom 8:34 Heb 7:25) Though requesting from the Father is part of the interceding activity, (Jn 14:16) the essence of Christ’s intercession is intervention in our interest (from his throne) rather than supplication on our behalf (as if his position were one of sympathy without status or authority). In sovereignty he now lavishes upon us the benefits that his suffering won for us. “He pleads for us – by his presence on his Father’s throne” (B. F. Westcott). “Our Lord’s life in heaven is his prayer” (H. B. Swete). From his throne he sends the Holy Spirit constantly to enrich his people (Ac 2:33; Jn 16:7-14) and equip them for service.’ (Eph 4:8-12) (Packer, Concise Theology)

Packer continues:

‘Jesus’ ascension was his Father’s act of withdrawing him from his disciples’ gaze upward (a sign of exaltation) into a cloud (a sign of God’s presence). This was not a form of space travel, but part two (the Resurrection being part one) of Jesus’ return from the depths of death to the height of glory. Jesus foretold the Ascension, (Jn 6:62; 14:2,12; 16:5,10,17,28; 17:5; 20:17) and Luke described it. (Lk 24:50-53; Acts 1:6-11) Paul celebrated it and affirmed Christ’s consequent lordship, (Eph 1:20; 4:8-10; Php 2:9-11; 1 Tim 3:16) and the writer of Hebrews applied this truth for encouragement of the fainthearted. (Heb 1:3; 4:14; 9:24) The fact that Jesus Christ is enthroned as master of the universe should be of enormous encouragement to all believers.’

The Ascension was from one standpoint the restoration of the glory that the Son had before the Incarnation, from another the glorifying of human nature in a way that had never happened before, and from a third the start of a reign that had not previously been exercised in this form.