Thou hast ascended in glory, O Christ our God, and gladdened thy Disciples with the promise of the Holy Spirit, having become confident of the blessing. Verily, thou art the Son of God, and Deliverer of the world.
After Jesus rose from the dead, He spent forty days on earth teaching His disciples. On the fortieth day, after instructing them to wait for the descent of the Holy Spirit, while at Mount of Olives, He was taken up into the heavens in a cloud. Then two angels in white clothes said to the disciples, "Ye men of Galilee, why stand ye gazing up into heaven? This same Jesus, which is taken up from you into heaven, shall so come in like manner as ye have seen Him go into heaven." Then the disciples returned to Jerusalem (Acts 1:9-11). In this icon Christ is above, with angels, being escorted back to His heavenly home. Below stand His Mother Mary, two angels in white, and the faithful disciples. Notice, it is Paul and Peter next to the Theotokos and there are 12 Apostles. This is not how it happened historically, but icons depict events with eternity in mind.