John Calvin Commentary John 16:9

"of sin, because they believe not on me;" — John 16:9 (ASV)

Of sin. It now remains for us to see what it is to convince of sin. Christ appears to make unbelief the only cause of sin, and this is tortured by commentators in various ways; but, as I have already said, I do not intend to detail the opinions that have been held and advanced.

First, it should be observed that the judgment of the Spirit begins with the demonstration of sin; for the beginning of spiritual instruction is that people born in sin have nothing in them but what leads to sin. Again, Christ mentioned unbelief to show what human nature is in itself, for, since faith is the bond that unites him to us, until we believe in him, we are outside of him and separated from him.

The meaning of these words is as if he had said, “When the Spirit is come, he will produce full conviction that, apart from me, sin reigns in the world”; and, therefore, unbelief is mentioned here because it separates us from Christ, as a result of which nothing is left to us but sin. In short, by these words he condemns the corruption and depravity of human nature, so that we do not suppose that a single drop of integrity is in us without Christ.