Jer 17:9-10 The heart is deceitful above all things, and desperately wicked: who can know it? I the LORD search the heart, I try the reins, even to give every man according to his ways, and according to the fruit of his doings.
If you find an apple with a worm hole, it does not mean there is a worm inside the apple. What happened is that an insect laid an egg in the apple blossom. Sometime later, the worm hatched in the heart of the apple, then ate its way out. Sin is in the very blossom of our human nature. Like the worm, it begins in the heart and works its way out through our thoughts, words, and actions. What we see coming out is what has been born on the inside. Man is not a sinner because he sins. He sins because he is a sinner. The only hope for a sinner's heart is the Lord Jesus Christ!