I always say that I am a Christian, because I belong to Christ. For purposes of discussion and debate with other believers I say that I agree with Calvin's or Paul's theology. But I think Paul states It best in 1 Corinthians 3: 4-9 :
4) For when one says, "I am of Paul," and another, "I am of Apollos," are you not mere men.
5) What then is Apollos? and what is Paul? Servants through whom you believed, even as the Lord gave opportunity to each one.
6) I planted. Apollos watered, but God was causing the growth.
7) So then neither the one who plants nor the one who waters is anything, but God who causes the growth.
8) Now he who plants and he who waters are one ; but each will receive his own reward according to his own labor.
9) For we are God's fellow workers; you are God's field, God's building.
I have no problem with what Luther said and think that Calvin would agree.
I fell you were trying to make a point and I agree that too often we tend to
identity with men rather then Jesus.