Jesus said unto them, If ye were blind, ye should have no sin: but now ye say, We see; therefore your sin remaineth.
Note 13 at Joh 9:41: "Sin is the transgression of the law" (1Jo 3:4, see also Ro 4:15). "Therefore to him that knoweth to do good, and doeth it not, to him it is sin" (Jas 4:17). God does not impute sin when there is ignorance. (This is not to say that there will be no judgment against those who have not heard the Gospel. Creation itself has declared that there is a God [Ps 19:1-4], and God has placed an intuitive knowledge of the Godhead inside every person [Ro 1:18-20]. God's judgment will be proportional to their knowledge [Lu 12:48].) But these Pharisees could not claim ignorance. They were simply rebellious. Paul said, "But I obtained mercy, because I did it ignorantly in unbelief" (1Ti 1:13). Mercy is available to those who are ignorant, but only judgment awaits those who willfully despise God's law (Heb 10:26-29).