James 4:17

Therefore, to the one who knows to do good and does not do [it], to him it is sin.

John 9:41

Jesus said to them, "If you were blind, you would not have sin. But now you say, 'We see,' your sin remains.

Luke 12:47-48

And that slave who knew the will of his master and did not prepare or do according to his will {will be given a severe beating}.

John 13:17

If you understand these [things], you are blessed if you do them.

John 15:22

If I had not come and spoken to them, they would not have sin. But now they do not have a valid excuse for their sin.

Romans 1:20-21

For from the creation of the world, his invisible [attributes], both his eternal power and deity, are discerned clearly, being understood in the things created, so that they are without excuse.

Romans 1:32

who, [although they] know the requirements of God, that those who do such things are worthy of death, not only do they do the same [things], but also they approve of those who do [them].

Romans 2:17-23

But if you call yourself a Jew and rely on the law and boast in God

Romans 7:13

Therefore, [did that which is] good become death to me? May it never be! Rather [it was] sin, in order that it might be recognized [as] sin, producing death through [what is] good for me, in order that sin might become sinful to an extraordinary degree through the commandment.

2 Peter 2:21

For it would have been better for them not to have known the way of righteousness than having known [it], to turn back from the holy commandment that had been delivered to them.

Treasury of Scripture Knowledge

Summary

Therefore to him that knoweth to do good, and doeth it not, to him it is sin.

Bible References

General references

Luke 12:47
And that slave who knew the will of his master and did not prepare or do according to his will {will be given a severe beating}.
John 9:41
Jesus said to them, "If you were blind, you would not have sin. But now you say, 'We see,' your sin remains.
John 13:17
If you understand these [things], you are blessed if you do them.
John 15:22
If I had not come and spoken to them, they would not have sin. But now they do not have a valid excuse for their sin.
Romans 1:20
For from the creation of the world, his invisible [attributes], both his eternal power and deity, are discerned clearly, being understood in the things created, so that they are without excuse.
Romans 2:17
But if you call yourself a Jew and rely on the law and boast in God
Romans 7:13
Therefore, [did that which is] good become death to me? May it never be! Rather [it was] sin, in order that it might be recognized [as] sin, producing death through [what is] good for me, in order that sin might become sinful to an extraordinary degree through the commandment.