When Christians confess their faith in God the Father Almighty, Creator of heaven and earth—that is Christian faith in the full sense of the term. And dogmaticians do not first divest themselves of their Christian faith in order to construct a rational doctrine of God and humanity … in order later to supplement it with the revelation in Christ. But they draw their knowledge solely and alone from special revelation, i.e., from Scripture. This is their unique principle.
From “Reformed Dogmatics”, Vol 1, pg 320.