At the beginning, man was formed in the image and resemblance of God, so that he might admire his Maker in the dignity with which God had so nobly invested him, and might honor him with appropriate thankfulness.
But man, trusting in the enormous excellence of his nature, and forgetting where it had come from and by whom it continued to exist, endeavored to exalt himself apart from the Lord. He therefore had to be stripped of all God’s gifts, on which he foolishly prided himself, so that, divested and deprived of all glory, he might know this God who had so enriched him by his generous gifts, and whom he had dared to despise.
This is why all of us — who owe our origin to Adam’s descendants, and in whom this resemblance to God is erased — are flesh born from flesh. For although we are made up of a soul and a body, we never feel anything but the flesh. The result is that whatever aspect of man we look at, it is impossible for us to see anything other than what is impure, irreverent, and abominable to God. For man’s wisdom, blinded and steeped in numberless errors, sets itself against God’s wisdom; the will, wicked and full of corrupt affections, hates God’s justice more than anything; and human strength, incapable of any good deed whatever, is furiously inclined towards iniquity.
John Calvin, Truth For All Time, p.6