A belated Pentecost thought, courtesy of T.F. Torrance - quotes are all from "Theology in Reconstruction", 253-258.
The office of the Holy Spirit in the Church is not to call attention to himself apart from Christ but to focus all attention on Christ, to glorify him, to bear witness to his deity, to testify to his mind and will, and in him and through him to lead us to the Father. He is God the Spirit by whom we know God, for he is God the Spirit by whom God bears witness to himself. Transparence and self-effacement thus belongs to the very nature and office of the Holy Spirit, as the Spirit of the Father and the Spirit of the Son, who is known only as the Father is known through the Son and the Son is known in the Father, and who together with the Father and the Son is worshipped and glorified as himself very God.
It is worth tugging at some of the threads in this quote to make sure we've understood them. Note that the Spirit is worshipped and glorified because he is himself God, true and full God; but he is not worshipped in the attention that we pay to him, but the attention that we pay by him to the Son, to Jesus Christ as he leads us to the Father. The Spirit is known, and known as God; but he is not known in himself, but only as he himself makes known the Father and the Son. Torrance summarises this by referring to the Spirit's transparence. He doesn't mean to imply by this any sort of insubstantiality, as if the Spirit could be 'seen through' because of his weightlessness and lack of solidity. We are dealing with the almighty, personal God when we are dealing with the Holy Spirit. The point is simply that the divine office of the Spirit as he is revealed to us in the Gospel is to make Christ known, and through and in him the Father. His almighty power is shown, not in itself, but in showing us the almighty power of the Father and the Son.
What really strikes me about the way that Torrance utilises this concept is that he sees the transparence of the Spirit as in some sense a transferrable quality. In thinking and speaking of God, we utilise human forms and concepts, which in themselves "are quite opaque as far as their reference to God himself is concerned." We simply don't have the ability to stretch our language up to God. "This is where the transparency of the Spirit comes in, for to be genuine our witness must be shot through and through with the uncreated light of God's self-revelation." We need the Spirit to make our words transparent to God's reality, to make them bearers of God's own light - something we can't do by ourselves.
Torrance extends this description of the transparency of the Spirit to Scripture - the perspicuity of the Scriptures means the fact that the Spirit causes the biblical witness to be transparent to divine reality - and baptism - in which we are meant to look "through the rite to Christ and his Gospel... Without Sacramental transparence Baptism becomes blind and meaningless."
We need - desperately need - the work of the Holy Spirit to make anything that we do with reference to God genuinely valuable and meaningful.
We recall too that this transparence comes from the Holy Spirit, from his own self-effacing nature and office in hiding himself, as it were, behind the Face of the Father in the Son and behind the Heart of the Son in the Father, yet revealing the one Triune God by letting his eternal light shine through himself to us.