The center of his being is self. True Christianity, whatever else it may be, cannot be less than right thinking, right feeling, and right actions in relationship to God. The evidences of saving religion, or being in Christ, are always present. Such is the unregenerate man. The primary evidence of being in Christ is that the power of these controlling factors is broken in one's union with Christ.
Old things become new, or to put it another way, new things now come.
There is a new purpose for living, a new path of obedience, and new practices. All things become new. That is the evidence of being in Christ. The person who is in Christ is renewed inwardly, not perfectly or finally, but in some measure in every part of his being. His heart and affections are renewed.