John 9:41

“If you were blind,” Jesus told them, “you wouldn’t have sin. But now that you say, ‘We see’—your sin remains.

Proverbs 26:12

Do you see a man who is wise in his own eyes?
There is more hope for a fool than for him.

Isaiah 5:21

Woe to those who are wise in their own opinion
and clever in their own sight.

Jeremiah 2:35

you claim, “I am innocent.
His anger is sure to turn away from me.”
But I will certainly judge you
because you have said, “I have not sinned.”

Luke 12:47

And that slave who knew his master’s will and didn’t prepare himself or do it will be severely beaten.

Luke 18:14

I tell you, this one went down to his house justified rather than the other; because everyone who exalts himself will be humbled, but the one who humbles himself will be exalted.”

John 15:22-24

If I had not come and spoken to them, they would not have sin. Now they have no excuse for their sin.

Hebrews 10:26

For if we deliberately sin after receiving the knowledge of the truth, there no longer remains a sacrifice for sins,

1 John 1:8-10

If we say, “We have no sin,” we are deceiving ourselves, and the truth is not in us.

Treasury of Scripture Knowledge

Summary

John 9:41

Jesus said unto them, If ye were blind, ye should have no sin: but now ye say, We see; therefore your sin remaineth.

General references

Matthew 13:13

Luke 11:35

James 4:17

Bible References

General references

For this reason I speak to them in parables, because looking they do not see, and hearing they do not listen or understand.

Take care then, that the light in you is not darkness.

So it is a sin for the person who knows to do what is good and doesn’t do it.