God manifests himself in three persons, the Father, the Son, and the Holy Spirit. It’s easy to recognize the Father and Son in many of our Christmas stories and traditions, but the Holy Spirit is sort of the missing character. That’s just in our remembrance of the story; in the Biblical account, he is all over that story.
If we’re aware of the Holy Spirit in the Christmas narrative at all, it’s probably when the angel Gabriel tells Mary that the Holy Spirit will come upon her and she will conceive, Luke 1:35. That’s just the first time Luke will mention the Spirit. In the following passage, Mary visits her cousin (or relative) Elizabeth. Elizabeth is six months with child, also a miraculous conception given her old age. The child she carries will become John the Baptist. As soon as Mary enters her home, Elizabeth is filled with the Holy Spirit and begins speaking. She is blessed that the mother of her Lord has come to see her, and also blesses Mary for believing God will fulfill his promises.
As soon as Elizabeth has finished speaking, Mary is filled with the Holy Spirit. She magnifies God and offers praise in a poetic monologue known as the Manificat. She says herself that all generations will call her blessed, just as Elizabeth has already spoken. The Holy Spirit is not finished yet; since doubting the words of the angel, when God’s plan was revealed to Zechariah, he has been stuck dumb (mute). At the time of John’s birth, Zechariah’s tongue is loosed, and guess what: he is filled with the Holy Spirit and begins to speak. His prophesy, in addition to praising God for sending salvation to the Gentiles and honor to his people Israel, is that his child will be the prophet of the Most High.
The last of the minor prophets, Malachi, lived about 400 years before Christ. There had not been a prophet in a while; no one had seen an angel nor had anyone been filled with the Holy Spirit for centuries. Now all of a sudden, as the Son of God is arriving on the scene, there is a whirlwind of activity. Angels are appearing to men and women, the shepherds witness the heavenly host, there is more than one miraculous birth, and the Holy Spirit once again speaks though people the words of God. He may be missing from our scenes of the nativity, but is very much a part of this story.