One of the most neglected parts of the incarnation accounts in the gospel records is that which touches on the presence and activity of the Holy Spirit in the life and ministry of Christ. We rightly wonder at the coming of the eternal Son of God into the world in true human form while wrongly neglecting to wonder at the accompanying role of the Spirit of God in the ministry of the Redeemer. Some of that is understandable. What greater mystery can there be than the mystery of Christ? He is the eternal mystery of God (1 Tim. 3:16). All God's revelation points to Him, and everything necessary for salvation flows from Him (Col. 1:15-22; Heb. 1:1-3). Yet, throughout the gospels the Spirit is revealed as the accompanying agent of redemption. He was active, from start to finish, in the life and ministry of Christ. This opens the important question, "Why was it necessary for the Spirit to be at work in the life and ministry of Christ from the virgin conception to his resurrection from the dead?" 

1. The Spirit came to indwell Jesus to sustain him as the Last Adam. The Spirit was the agent of the virgin conception, the anointing of Christ for ministry as Prophet, Priest and King at His baptism, and the leading of Christ into the wilderness to be tempted by the evil one. The Spirit is also the one by whom Christ cast out demons and overcame the kingdom of darkness. He was indwelling Christ as the Last Adam in order to enable Him to present Himself without blemish to God on the cross. The Spirit is also said to be the agent by whom Jesus was raised from the dead (Rom. 1:4; 8:11). 

To be the head of the new redeemed humanity, Jesus had to do all that he did in humble reliance upon the Holy Spirit. This began even before His birth. When Mary asked the Angel Gabriel how she would carry the Redeemer in her womb, since she was a virgin, Gabriel told her, "The Holy Spirit will come upon you, and the power of the Most High will overshadow you; therefore the child to be born will be called holy—the Son of God" (Luke 1:35). Just as the Spirit hovered over the waters of creation, so He hovered over the virgin Mary at the great work of bringing about the new creation through the incarnation of the Son of God.

Christ was dependent upon the Spirit for His miraculous works. If Jesus had simply performed miracles by his divine nature, then the divine nature of the eternal Son would have imparted to the human nature something (e.g. omnipotence) that is not proper to human nature and so destroy the human nature. Jesus acted as fully God and fully man in one person in all that He did. However, as the Last Adam, he had to rely on the Spirit to impart to him the grace He needed to do such things as perform miracles of healing. 

Jesus also needed the Holy Spirit for His own consecration and to sustain Him in sinlessness. Fallen humanity doesn't not need a superhuman holiness; what we need is a human holiness. Jesus came to do what Adam failed to do–namely, to obey the commands of God in the place of His people. The earthly ministry of our Lord Jesus, from start to finish, was a record of His perfect obedience and Law-keeping. Herman Ridderbos summed up the totality of Jesus' law-keeping when he wrote: "Jesus behaves in accordance with the precepts of the law when he goes to the temple, keeps the festivals, the Sabbath, pays the temple-tax (Matt. 17:24ff)...refers to the priest the lepers he had cured (Matt. 8:4), defends the sacred character of the temple against those who use this building as an object of gain (Matt. 21:12; Mark 11:16)."

Phil Ryken makes the important observation that "What qualified Jesus to redeem us from the law was the fact that he kept it perfectly." William Still put it in even more stiking terms when he suggested, "The most victorious thing that Christ ever did was to die sinless." This is one of the foremost reasons why Jesus needed the Spirit in the incarnation.

2. The Spirit came to bring the fuller revelation of Christ. The presence of the Spirit and the activity of the Spirit marked the dawning of a new age. The Spirit had been withdrawn from the old covenant people for nearly fourhundred years. Over four centuries, He had not given any new word of revelation. There were no accompanying sign-miracles during that period, until just prior to the coming of Christ. God had suspended the presence and activity of the Spirit between the Old Testament canon and the coming of Christ. Jonathan Edwards explained the significance of the Spirit returning at this new period of redemptive history. He wrote, 

"The return of the Spirit; which indeed began a little before, but yet was given on occasion of his birth. I have before observed how the spirit of prophecy ceased, not long after Malachi. From about the same time visions and immediate revelations ceased also. But on this occasion, they were granted anew, and the Spirit in these operations returns again. The first revealed instance of its restoration is the vision of Zachariah, the father of John the Baptist, (Luke 1.) The next is the vision which the Virgin Mary had, (ibid.) The third is the vision which Joseph had, (Matt. 1.) In the next place, the Spirit was given to Elisabeth, (Luke 1:41.) Next, it was given to Mary, as appears by her song, (Luke 1:46, &c.) Then to Zacharias again, (ibid. ver. 64.) Then it was sent to the shepherds, (Luke 2:9.) Then it was given to Simeon, (Luke 2:25.) Then to Anna, (ver. 36.) Then to the wise men in the east. Then to Joseph again, directing him to flee into Egypt; and after that directing his return." 

In John 16:14, Jesus said that the Spirit would bring Him glory by revealing all the truth about him to his people. This was, no doubt, reference to the fuller revelation that the Spirit would breath out through the Apostles. However, that fuller revelation began at the inauguration of the entry of the Son into this world. The Spirit is the agent of the divine revelation. It is no wonder that He is so active in giving that revelation to the central figures in the nativity accounts, after such a long time of withholding more revelation. 

3. The Spirit would be the agent of the application of redemption. How can it be possible for Christ to have died thousands of years ago and yet the benefits of His death and resurrection are effectual in the lives of believers? The answer is bound up in the activity of the Spirit at the cross. The writer of Hebrews, in what is one of the most astonishing verses in the Bible, writes, "The blood of Christ, who through the eternal Spirit offered himself without blemish to God, purifies our conscience from dead works to serve the living God" (Heb. 9:14). The blood of Jesus is sanctifying blood when it is applied to the consciences of believers by the Holy Spirit. The Spirit is able to apply the blood of Christ to the believer's conscience because He was present with Jesus on the cross. The same Spirit who enabled Jesus to die sinlessly––when offering Himself as an atoning sacrifice for the sins of His people––is the Spirit who now indwells believers and cleanses our consciences from the guilt and corruption of our polluted hearts.

As we celebrate the incarnation anew, fixing our minds on the wonders of the mystery of Christ, let's remember the presence and activity of the Spirit in the events surrounding the nativity. The Spirit who was forming a human nature for the Son in the womb of the virgin Mary and bringing the Son back from the dead in the darkness of the tomb is the same Spirit who indwells believers and conforms us to the image of the Son. That's the Spirit of Christmas we most deserately need.