4There is one body and one Spirit—just as you were called to the one hope that belongs to your call— 5one Lord, one faith, one baptism, 6( one God and Father of all, who is over all and through all and in all.
I read this and I find myself asking, "Why all the focus on the oneness of everything? I know the importance of unity, but what is he getting at?
So I go back a few verses. Paul considers himself a prisoner of God, a bond servant. My thoughts wander, maybe he is attacking something cultural. Back then, people would grab onto just about anything when it comes to faith. (Things haven't really changed much, have they?) So perhaps Paul is clarifying the unchanging nature of God and of Paul himself.
First, God. There is one God, one hope, one faith, one baptism, etc. But we like options. If I don't like your God, I can find one that suits me. If there is only one God, that severely limits my options.
Second, Paul. He is committed. He has sold out to the one God, and is not going to change his message when things don't go the way he wants them to.
There is one God. Am I willing to serve Him on His terms? There is one me. Or is there?