Isaiah 64:6 agrees: all our righteous acts are like filthy rags, highlighting human sinfulness and inability to be truly righteous.

1 John 1:8-10 directly affirms that claiming to be without sin is self-deception — a clear restatement of universal sinfulness.

James 3:2 echoes the same truth: everyone stumbles in many ways, reinforcing that no one is sinless.

In Romans 3:10, Paul quotes 'None is righteous, no, not one' — the same assertion that no one is without sin.

In Isaiah 53:6, 'All we like sheep have gone astray' declares universal sin — matching Ecclesiastes' claim of no righteous person.

In Proverbs 20:9, the rhetorical question 'Who can say, I have made my heart pure?' reinforces that no one is without sin.

In Psalm 143:2, David states 'no one living is righteous before you' — directly affirming the same truth.

In Psalm 130:3, the psalmist says 'if you should mark iniquities, who could stand?' — implying universal sinfulness.

In Job 15:14-16, Eliphaz asks 'What is man, that he can be pure?' — echoing the claim that no one is righteous and sinless.

In 2 Chronicles 6:36, this identical phrase 'for there is no one who does not sin' appears in Solomon's prayer.

In 1 Kings 8:46, Solomon says 'there is no one who does not sin' — the same universal sinfulness stated here.

In Daniel 9:20, Daniel confesses 'my sin and the sin of my people' — a practical admission that echoes the universal sinfulness.

Romans 3:12 states 'there is no one who does good, not even one' — a direct scriptural echo of Ecclesiastes' assertion.

Genesis 20:2 shows Abraham lying — another example that even the righteous patriarch sinned, confirming Ecclesiastes' point.

Romans 7:15 shows Paul's struggle with sin — a firsthand example of the universal sinfulness Ecclesiastes declares.

Romans 7:23 describes the law of sin waging war against the mind — the same universal human inability to do good without sin that Ecclesiastes 7:20 states.

In Galatians 2:13, even Peter and Barnabas act hypocritically, illustrating that no one is perfectly righteous as Ecclesiastes 7:20 states.

Philippians 3:9 presents righteousness through faith, not works, as the solution to the lack of self-righteousness in Ecclesiastes 7:20.

Genesis 9:21 records Noah's drunkenness — an example of the very sinfulness Ecclesiastes says is universal.

Genesis 8:21 states that every human heart is evil from childhood, directly supporting the universal sinfulness of Ecclesiastes 7:20.

Galatians 5:17 explains the internal conflict between flesh and Spirit, showing why even believers cannot be sinless as Ecclesiastes 7:20 says.

Genesis 6:9 calls Noah righteous, contrasting Ecclesiastes' claim that no one is — showing different senses of 'righteous'.