“In the pride of his face the wicked does not seek him; all his thoughts are, ‘There is no God.’ ” —Psalm 10:4
There is not in my judgement, a Psalm which describes the mind, the manners, the works, the words, the feelings, and the fate of the ungodly with so much propriety, fullness, and light as this Psalm. So that, if in any respect there has not been enough said heretofore, or if there shall be anything wanting in the Psalms that shall follow, we may here find a perfect image and representation of iniquity.” —Martin Luther
All sin is atheistic. It matters not what your creed may be, sin is functional atheism. Sin behaves as though God were not.
Sin seeks to de-god God and to deify man. As in the garden, sin disbelieves God’s threat, and trusts the promise of God-likeness.
The puritan Ralph Venning, writing at a time when plagues were dreaded, in a book originally titled The Plague of Plagues, captured this well. “In short, sin is the dare of God’s justice, the rape of his mercy, the jeer of his patience, the slight of his power, the contempt of his love, as one writer prettily expresses this ugly thing. We may go on and say, it is the upbraiding of his providence (Psalm 50), the scoff of his promise (2 Peter 3:3-4), the reproach of his wisdom (Isaiah 29:16). And as is said of the Man of Sin (i.e. who is made up of sin) it opposes and exalts itself above all that is called God (and above all that God is called), so that it as God sitteth in the temple of God, showing itself as if it were God (2 Thessalonians 2. 4).”
Sin is atheistic. Yea, it is more. It is anti-theistic, anti-God, anti-Christ. Who is anti-Christ? The whole of fallen humanity.
No Other Boast 