The Lord explains still further what the Holy Ghost would accomplish, what He would bring and teach us: “He will reprove the world of sin, and of righteousness, and of judgment.” Indeed a great task, so vast that its execution seems impossible. Not merely one school, or one village, or one city, or even several of them, but the whole world shall come under the influence and reproof of the Holy Spirit. It must in truth be a mighty power which can accomplish such a task, and it must be sure of the necessary support. To the world belong all the descendants of Adam, emperors, kings and princes. All these are included among the number of those whom the Holy Ghost, through the preaching of the apostles and other ministers, is to reprove and admonish. He tells them: Ye are all sinners; not one of you is just or wise, whether you live in Jerusalem or in Rome, whether you are of high or low degree; you must all learn true wisdom of me, or not one of you will be saved. If you despise my teachings, you shall all go to hell, just as you are, with your entire baggage of self-righteousness, of holiness and good works. Thus, says Christ to His disciples, will the Holy Spirit execute His office of reproving the whole world through you, the poor and despised preachers of the Gospel.
This reproof, however, is no idle sound, but dread reality. Christ says: “He will reprove the world of sin, and of righteousness, and of judgment.” What now, if there is in the world no righteousness, no judgment, nothing but sin – what shall become of us? Hence the reproof of the Holy Ghost is for the world a terrible shock; we hear that we are the devil’s own, with all our good works, and that we cannot enter into the kingdom of God unless the Holy Ghost removes our sins, makes us righteous, and frees us from judgment. Many passages in the Scriptures are of similar import. Thus St. Paul says: “God has concluded all under sin;” and again: “We were by nature children of wrath.” Christ also says: “Unless a man be born again he cannot enter into the kingdom of God.” With such words and declarations the Holy Ghost reproves the world of sin. (Luther’s House Postil, Fourth Sunday after Easter, Volume 2, p. 546-547)