John Lightfoot on John 16:8

[He will reprove the world of sin, &c.] The Holy Spirit had absented himself from that nation now for the space of four hundred years, or thereabout: and therefore, when he should be given and poured out in a way and in measures so very wonderful, he could not but evince it to the world that "Jesus was the true Messiah," the Son of God, who had so miraculously poured out the Holy Spirit amongst them; and consequently could not but reprove and redargue the world of sin, because they believed not in him.