Clint has suggested a detour from the Lutheran Confessions to the Spirit. I'm game.
Why not start at the beginning? Genesis 1, 2 says: "the earth was a formless void and darkness covered the face of the deep, while a wind from God swept over the face of the waters." Verse 3: "Then God said, 'Let there be light'; and there was light." (NRSV).
The Old Testament uses the same word for wind and breath as spirit or Spirit. At any rate, the NRSV chooses to translate "ruach Adonai" as "a wind from God" rather than "the spirit of God." This choice choice corresponds to one set of prejudices to the text: that it is not appropriate to interpret the text from Christian presuppositions. The latter "Christian" reading does not compete with most of Rabbinic readings since many of the Rabbis argued that the Ruach of God, God's spirit or breath would not in any case be one thing in the act of creation and the other instances where the spirit shows up.
The reason we are leaving spirit in the lowercase is the ambiguity and place that the Spirit has in the Old Testament. Whose spirit is it? YHWH's and no others. There are other spirits and other 'powers' but there is only one that belongs to YHWH. But, can the Old Testament say that the Spirit is "The Lord, the Giver of Life" as we do in the Creed? To approach this problem is to come close to the difficulties early Christians had in calling Jesus and the one Jesus called Father both Lord. Paul's argument in 1 Cor 8: "...even though there may be so-called gods in heaven or on earth ... yet for us there is one God, the Father, from whom are all things and for whom we exist, and one Lord, Jesus Christ, through whom are all things and through whom we exist" of course is precisely the difficulty most Jews faced. How is it that the LORD, who is the Creator and all else is creation, can be both the Father of Jesus and Jesus? Here we approach the threshold of thinking about the Trinity.
The place of the Spirit in our passage from Genesis also has this problem. Creation is one thing and the Creator another. How do we split the difference when the Bible never sees things in terms of "grades" of God and gods. There is never one being who is 100% God, then one who is 85%, then 50% and so on. There is only one God, the Father of Jesus, says Paul. That much, makes sense. But how on earth do we make sense of the "One Lord, Jesus Christ," much less "The Lord who is the Spirit" (2 Cor 3)?
The second verse has many problems to it that make many biblical scholars decide against thinking of the "ruach adonai" as the Spirit. The chief one stems not from this verse but the first verse of the Bible: "In the beginning God created the heavens and the earth." Is this a summary of the whole creation story or is it the first act? If it is the summary only, then verse 2, our verse, describes the state of affairs before God began to create in verse 3.
So much for the sharp difference between Creator and creature? Not necessarily. But to understand the Spirit we do not have to solve this problem. Here we are talking about the Spirit as wind, as breath. This contributes to our understanding of the Spirit by pointing away from thinking of the Spirit as an impersonal blast of power or as a sort of spooky thing, a numinous reality that sort of is "out there." We do better to recognize that the Spirit's reality is intimate in creation. The Spirit is nothing supernatural but is grounded in the Creator's own will and love for you. The Spirit is not a something that is on the lose in the sense of "who knows what it will do next." The Spirit rather is deeply involved in the creation's life. The Spirit is there from the beginning of creation and belongs to the Creator's deep love for creation to exist. After all, the Spirit's brooding is intertwined with God's speaking: "let there be light."
In the broadest sense, thinking on this lesson together with Mary's Magnificat in Luke 2, Luther points the way: God has acted through his Spirit in Jesus, in you and me, in creation just as he has ever since the beginning. God takes something and makes it into nothing and takes nothing and makes it into something. God comes to a young girl who freely consents to be the mother of Jesus. God comes to the cross of that Jesus and says even in the face of death and the world of evil: I am still God, I am God and am glorified by the death of my beloved Son. And the Spirit comes, brooding over the grave, raising Jesus from the dead. And that same Spirit comes to you, giving you that smae cross and promising new life.