Contradiction with Ecclesiastes 7:20
This verse states that there is not a just man on earth who continually does good and does not sin, which contradicts Psalms 18:21's implication of blamelessness.
Ecclesiastes 7:20: For [there is] not a just man upon earth, that doeth good, and sinneth not.
Contradiction with Romans 3:23
This verse asserts that all have sinned and fall short of the glory of God, contradicting the idea of keeping all God's ways without turning aside.
Romans 3:23: For all have sinned, and come short of the glory of God;
Contradiction with 1 John 1:8
This verse claims that if we say we have no sin, we deceive ourselves, contrasting with the adherence to blamelessness in Psalms 18:21.
1 John 1:8: If we say that we have no sin, we deceive ourselves, and the truth is not in us.
Contradiction with Isaiah 64:6
This verse describes all our righteous acts as filthy rags, which contradicts the claim of maintaining righteousness in Psalms 18:21.
Isaiah 64:6: But we are all as an unclean [thing], and all our righteousnesses [are] as filthy rags; and we all do fade as a leaf; and our iniquities, like the wind, have taken us away.
Contradiction with Romans 7:19
Paul discusses the struggle with sin, indicating inability to perfectly keep God's ways, opposing the claim of blamelessness found in Psalms 18:21.
Romans 7:19: For the good that I would I do not: but the evil which I would not, that I do.
Paradox #1
Psalms 18:21 might seem to contradict or conflict with the idea that humans are inherently flawed and need forgiveness, which is a common theme in the Bible. This verse might be interpreted as suggesting that someone has perfectly kept God's ways, which could seem inconsistent with the belief in human imperfection and the need for God's grace.