Barth has some really good things to say about the Person of the Holy Spirit:
In what has been said we have stated already that according to the testimony of Scripture the Holy Spirit is no less and no other than God Himself, distinct from Him whom Jesus calls His Father, distinct also from Jesus Himself, yet no less than the Father and no less than Jesus, God Himself, altogether God. (CD 1.1, 459)
notes follow this discussing 2 Cor 3:17, John 4:24; Acts 5:3ff; Mark 3:28,29 where Barth writes: however we may understand it, there could not possibly be a blasphemy against the Holy Ghost which makes man guilty of an unforgivable, eternal sin, if the Spirit were less or something other than God himself.
That not only these and similar verses but the whole New Testament doctrine of the work of the Holy Spirit implies the deity of His essence can properly be contested only if one has first explained away the fact that with its “Iesous Kurios” the New Testament community confessed its faith in Jesus Christ as faith in God Himself. If the Christ of the New Testament is a demi-god from above or below, then naturally faith in Him becomes a human possibility. Then, extraordinary though the phenomenon may be, one can show how faith in Him has arisen on certain grounds and presuppositions which we ourselves can perceive and control. But in this case there is in fact no need for the deity of the Holy Spirit who creates this faith. On this view the name “Holy Spirit” may very well be a mere name for a particularly profound, serious and vital conviction of truth or experience of conscience, or one may equally well omit it altogether when describing the basis of faith according to the New Testament. (CD, 1.1, 460).
So, in sum, the Holy Spirit is God and is as much God as the Father and the Son though distinct from them – He is not merely some extention of them but rather, he is his own person. He is not “a mere name for a particularly profound, serious and vital conviction of truth or experience of conscience,” rather, he is God! God the Spirit. Our Lord and Life Giver! The Holy Spirit is not some spooky feeling one gets or the warming of the heart some experience or any thing of any such notion – the Holy Spirit is God and because he is God, he is a person with personality, with a will and a purpose – what is the purpose? To reveal to us God the Father and God the Son. To conform us into the image of Jesus Christ. To work in and through us the will and purposes of the Father for our lives and for his Kingdom in this world.
I guess all this isn’t exactly a newsflash or anything, most of us know and understand the Holy Spirit to be God – but I think we need the reminder now and again – that the Holy Spirit is altogether God. This is important because I think one tendency in the church at large is the tendency to go the opposite direction of what we see in many a charismatic setting – we don’t want to be all over the top in our pursuit of a life in the Spirit yet, when we go too far the other way, we need to be reminded that we are seriously at risk of leaving out God himself from our pursuit of him! Strange as it may seem, that can happen. It is okay to pursue a life in the Spirit – for in so doing, we are pursuing a life in God!