Behold Your God, Dealing with a Sinful Nature
If we're going to address the subject of a sinful nature, we have to go back to Adam and the original sin. Adam's choice caused God to banish him and Eve from the garden and that was only the beginning of humanity's isolation from God. Sin did not merely change extermal conditions--something was terribly altered within us.
Paul speaks of sin as "spiritual death". He quotes old testament scripture:
"As it is written: There is none righteous, no, not one; there is none who understands; there is none who seeks after God; they have all turned aside; they have together become unprofitable; there is non who does good, no, not one." NIV Psalms 14:1-3, 53:1-3
Man cannot know God, find God on His own. It is impossible. I think that is what frustrates a lot of people who look for God in the wrong places, in the wrong ways--selfish reasons, prideful reasons. They say they've tried to no avail and given up.
Psalms 10:4 "In his pride, the wicked man does not seek Him, in all his thoughts there is no room for God."
Pride was the root of both Satan's and Adam's rebellion. We know we aren't perfect, but we flatter ourselves that we are not particularly needy either. We are enamored with our inflated views of ourselves and refuse to humble ourselves and seek Him.
Jeremiah 9 is full of Israel's attempts to deceive.
Acts of deceit
vs 2-3 "Oh, that I had in the desert a lodging place for travelers, so that I might leave my people and go away from them; for they are all adulterers, a crowd of unfaithful people. They make ready their tongue like a bow to shoot lies; it is ot by truth that they triumph in the land. They go from one sin to another; they do not acknowledge me, declares the Lord."
Unnatural degree of dishonesty
v 4-5 "Beware of your friends; do not trust anyone in your clan. For every one of them is a deceiver, and every friend a slanderer. Friend deceives friend, and no one speaks the truth. They have taught their tongues to lie; they weary themselves with sinning."