in regard to sin, because they do not believe in Me;

John 15:22
If I had not come and spoken to them, they would not be guilty of sin. Now, however, they have no excuse for their sin.

John 15:24
If I had not done among them the works that no one else did, they would not be guilty of sin; but now they have seen and hated both Me and My Father.

John 16:8
And when He comes, He will convict the world in regard to sin and righteousness and judgment:

Of sin, because they believe not on me;