This calls to be what you are not, the exact opposite of what you claim as you say "Become and live what you are already" in order to "prove" the will of God true".
As Christians, our salvation is complete. Our becoming like-Christ is a life-long and into eternity process. For we do not know what we shall be, but we shall be like Him. We are in the process of being transformed - and part of that process is what we are doing right now. Discussing His Word.