An excerpt from Professor Thomas F. Torrance’s essay, “Come, Creator Spirit, for the Renewal of Worship and Witness,” in his book Theology in Reconstruction, (Grand Rapids: Wm. B. Eerdmans Publishing Company, 1975 reprint). p 241.
“With the Incarnation, God the eternal Son became Man, without ceasing to be God and without breaking the communion of the Holy Trinity within which God lives his own divine life. In the birth and life of Jesus on earth human nature and divine nature were inseparably united in the eternal Person of God the Son. Therefore in him the closed circle of the inner life of God was made to overlap with human life, and human nature was taken up to share in the eternal communion of the Father and the Son in the Holy Spirit. In this one Man the divine life and love overflowed into creaturely and human being, so that Jesus, Man on earth, received the Spirit of God without measure, for the fulness of the Godhead dwelt in him bodily. Jesus became the Bearer of the Holy Spirit among men.
“But who was Jesus? He was very Man, our Brother. In him the Holy Son of God was grafted on to the stock of our fallen human existence, and in him our mortal and corrupt human nature was assumed into union with the Holy Son of God, so that in Jesus, in his birth and sinless life, in his death and resurrection, there took place a holy and awful judgment on our flesh of sin, and an atoning sanctification of our unholy human existence. It was only through such atonement that God in all his Godness and holiness came to dwell in the midst of mortal, sinful man. Because that took place in Jesus who made our flesh of sin his very own and who wrought out in himself peace and reconciliation between man and God, he became not only the Bearer but the Mediator of the Holy Spirit to men.
“Now we may understand the distinctively new mode of the Spirit’s coming into the experience of men. The inner life of the Holy Trinity which is private to God alone is extended to include human nature in and through Jesus. This is possible because of the atonement that took place in him, for now that the enmity between God and man has been abolished, God the Holy Spirit may dwell in the midst of mortal sinful man. This is the way that the divine love has taken to redeem man, by making him share in the holy power in which God lives his own divine life. The pouring out of that power from on high took place at Pentecost, with the entry of the Holy Spirit in his new mode of presence and activity into the experience of mortal men.”