“To be conformed to the image of Christ is not an ideal to be striven after. It is not as though we had to imitate him as well as we could. We cannot transform ourselves into his image; it is rather the form of Christ which seeks to be formed in us (Gal. 4.19), and to be manifested in us. Christ’s work in us is not finished until he has perfected his own form in us...
“His life on earth is not finished yet, for he continues to live in the lives of his followers. Indeed it is wrong to speak of the Christian life: we should speak rather of Christ living in us. ‘I live, and yet no longer I, but Christ liveth in me’ (Gal. 2.20). Jesus Christ, incarnate, crucified and glorified, has entered my life and taken charge. ‘To me to live is Christ’ (Phil. 1.21). And where Christ lives, there the Father also lives, and both Father and Son through the Holy Ghost. The Holy Trinity himself has made his dwelling in the Christian heart, filling his whole being, and transforming him into the divine image.”
Dietrich Bonhoeffer, The Cost of Discipleship