The Holy Spirit is such a minimized character within the triadic unfolding of God, partly because this is His mission—to bear witness and magnify Jesus—and partly because if He has received any attention, often times it is in an abused way (i.e. pentecostalism). The Holy Spirit, historically, has been thought of as the linch-pen who subjectifies, for us, the objective work of Christ. He is the One who, eternally functions as the communal personage that completes the interpenetrating (i.e. perichoretic) stasis of Father and Son. He subjectively brings us into this communion, by uniting us with Christ through His humanity, and into His divinity. This is why Paul can say:

. . . But he who is joined to the Lord is one spirit with Him. ~ I Corinthians 6:17

So much beyond the minimalist and abusive notions that accompany thinking about the Holy Spirit today, there is a richness about Him, that can only be fully appreciated within the context of Jesus’ incarnation, which He bears witness to, and the subsequent fullness of Joy He brings us into as our union with Christ becomes the occasion for knowing the Father. Once again Torrance has this insightful plus for our consideration:

Like Christ the Holy Spirit is one in being and of the same being as the Father, but unlike Christ the Holy Spirit is not one in being and of the same being as we are, for he incarnated the Son but does not incarnate himself, he utters the Word but does not utter himself. He directs us through himself to the one Word and Face of God in Jesus Christ in accordance with whom all our knowledge of God is formed in our minds, knowledge of the Spirit as well as of the Father and of the Son. This is the diaphanous self-effacing nature of the Holy Spirit who hides himself, as it were, behind the Father in the Son and behind the Son in the Father, but also the enlightening transparence of the Spirit who by throwing his eternal Light upon the Father through the Son and upon the Son in the Father, brings the radiance of God’s Glory to bear upon us. We do not know the Holy Spirit directly in his own personal Reality or Glory. We know him only in his unique spiritual mode of activity and transparent presence in virtue of which God’s self-revelation shines through to us in Christ, and we are made through the Spirit to see the Father in the Son and the Son in the Father. While the Holy Spirit thereby guards the transcendence of God who infinitely exceeds what finite minds can grasp, nevertheless through his personal presence to us he brings the ineffable Being and Reality of God out of his unapproachable Light to bear upon us, and brings us out of our distance and darkness to have communion with himself and through himself with the Father and the Son. Because through him the Word of God continues to sound forth and is heard and believed, because in his light we see light and by his creative operation we come to know the unknowable and eternal God, we know the Holy Spirit, although personally distinct from the Father and the Son, to be no less Lord God than the Father and the Son, both as he is toward us and as he is antecedently in the undivided oneness of God’s eternal being. (Thomas F. Torrance, “The Christian Doctrine of God: One Being Three Persons,” 66-7)