The following is taken from the book "Meditations for Advent, Preparing for Christ's Birth" by Fr Vassilios Papavassiliou, published by Ancient Fath Publishing.
The last part in this series looks at the meaning of the star that led the Wise Men (Magi) to where the King of kings was born.
Another popular theme and image of the Nativity is the Star of Bethlehem. This is yet another prophecy from the Old Testament:
I will show Him, but not now; I bless Him, but He is not near. A Star shall rise out of Jacob; and a Man shall rise out of Israel. (Numbers 24:17)
Many assume that the Star of Bethlehem was an astronomical phenomenon. St John Chrysostom (4th century) did not agree. He gives four reasons the Star of Bethlehem was not really a star:
That this star was not ordinary one - or rather not a star at all, in my opinion - but some invisible power in the form of a star, is in the first place evident from its course. For not one of the stars moves like this, but whether you take the sun, or the moon, or all the other stars, we see them going from east to west; but this one travelled from north to south - for Palestine lies south of Persia (recall that the Wise Men travelled from Persia to Palestine).
Chrysostom, like other Church Fathers, compares the Star of Bethlehem to the pillar of cloud and the pillar of fire in Exodus 13:21-22, which are clearly manifestations of God Himself:
And the Lord went before them by day in a pillar of cloud to lead them along the way, and by night in a pillar of fire to give them light, that they might travel by day and by night. The pillar of cloud by day and the pillar of fire by night did not depart from before the people. (Exodus 13:21-22)
Another manifestation of God in a cloud and an instance in which the light of God shone brighter than the sun in the Transfiguration of Christ on Mount Tabor:
After six days Jesus took with him Peter and James and John his brother, and led them up a high mountain apart. And he was transfigured before them, and his face shone like the sun, and his garments became white as light. And behold, there appeared to them Moses and Eli′jah, talking with him. And Peter said to Jesus, “Lord, it is well that we are here; if you wish, I will make three booths here, one for you and one for Moses and one for Eli′jah.” He was still speaking, when lo, a bright cloud overshadowed them, and a voice from the cloud said, “This is my beloved Son, with whom I am well pleased; listen to him." (Matthew 17:1-5)
The bright cloud of Tabor is also compared by the Church Fathers to the pillar of cloud in the Old Testament, and the blinding light of the Transfiguration is considered a manifestation of the Uncreated Light - that is to say, the Light of God Himself. This may be the reason that the light of the Star of Bethlehem in the icons of the Nativity is painted in exactly the same way as the light of God on Mount Tabor in the icons of the Transfiguration.
The Star of Bethlehem was no star, but a manifestation of the Holy Spirit. He testifies to the Son of God, who bears witness to the Father.