John Lightfoot on John 15:22

[They had not had sin.] So also verse 24: in both places the passage is to be understood of that peculiar sin of rejecting the Messiah: "If I had not spoken to them, and done those things that made it demonstrably evident that I was the Messiah, they had not had sin, that is, they had not been guilty of this sin of rejecting me. But when I have done such things amongst them, it is but too plain that they do what they do in mere hatred to me and to my Father." Our Saviour explains what sin he here meaneth in chapter 16:9.