The Berean - Genesis 3:7-11 NASB
(7) Then the eyes of both of them were opened, and they knew that they were naked; and they sewed fig leaves together and made themselves loin coverings. (8) They heard the sound of the LORD God walking in the garden in the cool of the day, and the man and his wife hid themselves from the presence of the LORD God among the trees of the garden. (9) Then the LORD God called to the man, and said to him, "Where are you?" (10) He said, "I heard the sound of You in the garden, and I was afraid because I was naked; so I hid myself." (11) And He said, "Who told you that you were naked? Have you eaten from the tree of which I commanded you not to eat?"
New American Standard Bible
This account of Adam's and Eve's reaction to their sin demonstrates that sin destroys innocence.
Were two people ever more innocent at the beginning of their lives than Adam and Eve? Immediately after sinning, though, they felt shame because of their nakedness, and they doubly showed their guilt by hiding from God. Do the truly innocent have any need to hide? Do the innocent need to feel shame?
Sin leaves a tarnish on a person's mind so that he does not look at life in quite the same way anymore. David expresses how this tarnish affected him in Psalm 40:12, "My iniquities have overtaken me, so that I am not able to look up." Paul later explains, "To the pure all things are pure, but to those who are defiled and unbelieving nothing is pure; but even their mind and conscience are defiled" (Titus 1:15).
A well-known series of scriptures, beginning in Matthew 18:1, touches on innocence and its destruction. It starts with a question from the disciples: "Who then is greatest in the kingdom of heaven?" Jesus replies that unless we become as little children, we will not be in the Kingdom of Heaven. Is not the beauty of their innocence and the harmless vulnerability of little children a major reason why we find them so adorable? They produce no harm, shame, or guilt. But what happens as they become adults? They become sophisticated, worldly, cosmopolitan, cynical, suspicious, sarcastic, prejudiced, self-centered, cool, uninvolved, and many other negative things. They also seem to lose their zest for life. Sin does that.
— John W. Ritenbaugh