John 16:7

I tell you … it is expedient for you that I go: that I leave you, as to my corporal presence: that I suffer death, for the redemption of all men. And if I go not, the Paraclete will not come, according to the order of the divine decrees: his coming to sanctify you with his gifts, and to teach you all things, is not to be till after my ascension. When I am gone, I will send him to you. The Father and I will send him, for he proceedeth from both. (Witham)

1. See here what the office of the Spirit is, and on what errand he is sent. (1.) To reprove. The Spirit, by the word and conscience, is a reprover; ministers are reprovers by office, and by them the Spirit reproves. (2.) To convince. It is a law-term, and speaks the office of the judge in summing up the evidence, and setting a matter that has been long canvassed in a clear and true light. He shall convince, that is, "He shall put to silence the adversaries of Christ and his cause, by discovering and demonstrating the falsehood and fallacy of that which they have maintained, and the truth and certainty of that which they have opposed." Note, Convincing work is the Spirit's work; he can do it effectually, and none but he; man may open the cause, but it is the Spirit only that can open the heart. The Spirit is called the Comforter (v. 7), and here it is said, He shall convince. One would think this were cold comfort, but it is the method the Spirit takes, first to convince, and then to comfort; first to lay open the wound, and then to apply healing medicines. Or, taking conviction more generally, for a demonstration of what is right, it intimates that the Spirit's comforts are solid, and grounded upon truth.

Verses 7-15 Christ's departure was necessary to the Comforter's coming. Sending the Spirit was to be the fruit of Christ's death, which was his going away. His bodily presence could be only in one place at one time, but his Spirit is every where, in all places, at all times, wherever two or three are gathered together in his name. See here the office of the Spirit, first to reprove, or to convince. Convincing work is the Spirit's work; he can do it effectually, and none but he. It is the method the Holy Spirit takes, first to convince, and then to comfort. The Spirit shall convince the world, of sin; not merely tell them of it. The Spirit convinces of the fact of sin; of the fault of sin; of the folly of sin; of the filth of sin, that by it we are become hateful to God; of the fountain of sin, the corrupt nature; and lastly, of the fruit of sin, that the end thereof is death. The Holy Spirit proves that all the world is guilty before God. He convinces the world of righteousness; that Jesus of Nazareth was Christ the righteous. Also, of Christ's righteousness, imparted to us for justification and salvation. He will show them where it is to be had, and how they may be accepted as righteous in God's sight. Christ's ascension proves the ransom was accepted, and the righteousness finished, through which believers were to be justified. Of judgment, because the prince of this world is judged. All will be well, when his power is broken, who made all the mischief. As Satan is subdued by Christ, this gives us confidence, for no other power can stand before him. And of the day of judgment. The coming of the Spirit would be of unspeakable advantage to the disciples. The Holy Spirit is our Guide, not only to show us the way, but to go with us by continued aids and influences. To be…