I have been crucified with Christ. It is no longer I who live, but Christ who lives in me. And the life I now live in the flesh I live by faith in the Son of God, who loved me and gave himself for me. —Galatians 2:20
The goal of the Christian life is to understand more fully the reality of Galatians 2:20. John Calvin explains:
But if we are not our own, but the Lord’s, it is plain both what error is to be shunned, and to what end the actions of our lives ought to be directed. We are not our own; therefore, neither is our own reason or will to rule our acts and counsels. We are not our own; therefore, let us not make it our end to seek what may be agreeable to our carnal nature. We are not our own; therefore, as far as possible, let us forget ourselves and the things that are ours.
On the other hand, we are God’s; let us, therefore, live and die to him (Romans 14:8). We are God’s; therefore, let his wisdom and will preside over all our actions. We are God’s; to him, then, as the only legitimate end, let every part of our life be directed. O how great the proficiency of him who, taught that he is not his own, has withdrawn the dominion and government of himself from his own reason that he may give them to God!
For as the surest source of destruction to men is to obey themselves, so the only haven of safety is to have no other will, no other wisdom, than to follow the Lord wherever he leads. Let this, then be the first step, to abandon ourselves, and devote the whole energy of our minds to the service of God. By service, I mean not only that which consists in verbal obedience, but that by which the mind, divested of its own carnal feelings, implicitly obeys the call of the Spirit of God.
This transformation, (which Paul calls the renewing of the mind, Romans 12:2; Ephesians 4:23) though it is the first entrance to life, was unknown to all the philosophers. They give the government of man to reason alone, thinking that she alone is to be listened to; in short, they assign to her the sole direction of the conduct. But Christian philosophy bids her give place, and yield complete submission to the Holy Spirit, so that the man himself no longer lives, but Christ lives and reigns in him (Galatians 2:20). (Institutes Book III)