Christians think of the festival of Christmas as the arrival of the Son of God in the world, or even as his descent into the world.

In terms of arrival, they are speaking in common sense language as when they say, "Her baby has arrived!" In fact, they mean arrived in a visible way in space and time so that the place and time of birth can be stated. (In fact there was an earlier arrival the conception 36 weeks earlier but not seen by human eyes.)

The Son of God with his divine nature exists from eternity unto eternity in the infinite divine sphere; but in terms of both the divine sense of time and human chronological time there was a moment when he arrived in space and time, and that moment was the conception of Jesus by Mary through the presence of the Holy Ghost. The act of Incarnation by the Son of God began at the conception by Mary of Jesus and came to its climax in the birth from Mary of Jesus. So the arrival of Jesus, Son of God and son of Mary, one Person, we date on Christmas Day. We also say in the Creed, "He descended from heaven and was incarnate of the Virgin Mary." So his arrival is also his descent.

Christians think of the Feast of the Ascension as the departure of the Son of God from earth and his ascent into heaven.

After his ministry as the Messiah, his death and burial as the sacrificed Lamb of God, and his being raised from the dead as the victorious Saviour, the resurrected Jesus visited his apostles and disciples for a period of forty days. Then he departed from them, not to be seen again in physical, bodily form. On the last of these forty days, in his final resurrection appearance, there was a clear demonstration to the assembled disciples of where precisely Jesus was going and where he would be for the future. The cloud into which he went up was no ordinary white cloud in the sky, but the luminous cloud of glory known in the Old Testament as the sign of the presence of YHWH, the LORD, and called by the Jews, the Shekinah. Thus he ascended into heaven, into the immediate presence of GOD.

Before he departed and ascended, he had taught them all that they needed to know about his identity and mission, and he had promised them the Paraclete (Counsellor, Advocate, Comforter - the Holy Ghost as the Spirit of Christ) to be with them all, wherever they were in space and time.

The descent of the Paraclete is what is celebrated on Whit Sunday, the Feast of Pentecost (Acts 2), ten days after the Ascension into heaven. We may say that the Lord Christ came to his people with and by the presence of the Holy Ghost.

And the exalted Lord Jesus will remain where he is in terms of his human nature - on the throne of glory- until he descends once more into space and time, until he arrives in glory on earth, in order to judge the living and the dead, consummate the purposes of God and inaugurate the new age of the kingdom of God. His coming and arrival in great glory is the Christian Hope.

In the interim, the period of the evangelisation of the world by the Church, the Holy Ghost is present to make the Lord Jesus known on earth and to enable the Church to ascend in heart and mind to dwell with the same Lord Jesus in heaven.