"But now the Gospel has brought about the restoration of that image. Intellect and will indeed have remained, but both very much impaired. And so the Gospel brings it about that we are formed once more according to that familiar and indeed better image, because we are born again into eternal life or rather into the hope of eternal life by faith, that we may live in God and with God and be one with Him, as Christ says (John 17:21).
"And indeed, we are reborn not only for this life but also for righteousness, because faith acquires Christ’s merit and knows that through Christ’s death we have been set free. From this source our other righteousness has its origin, namely that newness of life through which we are zealous to obey God as we are taught by the Word and aided by the Holy Spirit. But this righteousness has merely its beginning in this life and it cannot attain perfection in this flesh. Nevertheless, it pleases God, not as though it were a perfect righteousness or a payment for sin but because it comes from the heart and depends on its trust in the mercy of God through Christ. Moreover, this also is brought about by the Gospel, that the Holy Spirit is given to us, who offers resistance in us to unbelief, envy, and other vices that we may earnestly strive to glorify the name of the Lord and His Word, etc.
"In this manner this image of the new creature begins to be restored by the Gospel inn this life, but it will not be finished in this life. But when it is finished in the kingdom of the Father, then the will will be truly free and good, the mind truly enlightened, and the memory persistent....Just as in the beginning the heaven and the earth were unfinished masses, so to speak, before the light had been added, so the godly have within themselves that unfinished image which God will on the Last Day bring to perfection in those who have believed His Word.
"Therefore that image of God was something most excellent, in which were included eternal life, everlasting freedom from fear, and everything that is good."
Luther's Lectures on Galations, Chapters 1-5