John 3:12

Christ speaketh only of himself, though he speaketh in the plural number, for in the next verse he saith only, If I have told you earthly things; he lets Nicodemus know that he spake nothing but he was certain of. This he expresses by two words, know and have seen, which are terms expressive of the greatest certainty of a thing imaginable; for the terms express a certainty of the mind, arising both from the rational deduction and sensible demonstration: and herein our Saviour lets his ministers know what is their duty to teach unto people, viz. what they know and have seen. Those that think that the doctrine of the gospel would have no certainty but for the authority of the church, stand highly concerned to reflect upon this text. ye ought to believe what I tell you upon the authority of my revelation; but such is the hardness of your heart, such your stubbornness and unbelief, that you receive not my testimony.

Secondly, Jesus Christ is able, and fit, and every way qualified, to reveal the will of God to us; for it is he that came down from heaven and is in heaven. He had said (v. 12), How shall ye believe, if I tell you of heavenly things? Now here, 1. He gives them an instance of those heavenly things which he could tell them of, when he tells them of one that came down from heaven, and yet is the Son of man; is the Son of man, and yet is in heaven. If the regeneration of the soul of man is such a mystery, what then is the incarnation of the Son of God? These are divine and heavenly things indeed. We have here an intimation of Christ's two distinct natures in one person: his divine nature, in which he came down from heaven; his human nature, in which he is the Son of man; and that union of those two, in that while he is the Son of man yet he is in heaven. 2. He gives them a proof of his ability to speak to them heavenly things, and to lead them into the arcana of the kingdom of heaven, by telling them, (1.) That he came down from heaven. The intercourse settled between God and man began above; the first motion towards it did not arise from this earth, but came down from heaven. We love him, and send to him, because he first loved us, and sent to us. Now this intimates, [1.] Christ's divine nature. He that came down from heaven is certainly more than a mere man; he is the Lord from heaven, 1 Cor 15 47. [2.] His intimate acquaintance with the divine counsels; for, coming from the court of heaven, he had been from eternity conversant with them. [3.] The manifestation of God. Under the Old Testament God's favours to his people are expressed by his hearing from heaven (2 Chron 7 14), looking from heaven (Ps 80 14), speaking from heaven (Neh 9 13), sending from heaven, Ps 57 3. But the New Testament shows us God coming down from heaven, to teach and save us. That he thus descended is an admirable mystery, for the Godhead cannot change places, nor did he bring his body from heaven; but that he thus condescended for our redemption is a more admirable mercy; herein he commended his love. (2.) That he is the Son of man, that Son of man spoken of by Daniel (vii 13), by which the Jews always understand to be meant the Messiah. Christ, in calling himself the Son of man, shows that he is the second Adam, for the first Adam was the father of man. And of all the Old-Testament titles of the Messiah he chose to make use of this, because it was most expressive of his humility, and most agreeable to his present state of humiliation. (3.) That he is in heaven. Now at this time, when he is talking with Nicodemus on earth, yet, as God, he is in heaven. The Son of man, as such, was not in heaven till his ascension; but he that was the Son of man was now, by his divine nature, every where present, and particularly in heaven. Thus the Lord of glory, as such, could not be crucified, nor could God, as such, shed his blood; yet that person who was the Lord of glory was crucified (1 Cor 2 8), and God purchased the church with his own blood, Acts 20 28. So close is the union of the two natures in one person that there is a communication of properties. He doth not say hos esti. God is the ho on to ourano—he that is, and heaven is the habitation of his holiness.

[1.] That the truths Christ taught were very certain and what we may venture upon (v. 11): We speak that we do know. We; whom does he mean besides himself? Some understand it of those that bore witness to him and with him on earth, the prophets and John Baptist; they spoke what they knew, and had seen, and were themselves abundantly satisfied in: divine revelation carries its own proof along with it. Others of those that bore witness from heaven, the Father and the Holy Ghost; the Father was with him, the Spirit of the Lord was upon him; therefore he speaks in the plural number, as ch. 14 23: We will come unto him. Observe, First, That the truths of Christ are of undoubted certainty. We have all the reason in the world to be assured that the sayings of Christ are faithful sayings, and such as we may venture our souls upon; for he is not only a credible witness, who would not go about to deceive us, but a competent witness, who could not himself be deceived: We testify that we have seen. He spoke not upon hear-say, but upon the clearest evidence, and therefore with the greatest assurance. What he spoke of God, of the invisible world, of heaven and hell, of the divine will concerning us, and the counsels of peace, was what he knew, and had seen, for he was by him as one brought up with him, Prov 8 30. Whatever Christ spoke, he spoke of his own knowledge. Secondly, That the unbelief of sinners is greatly aggravated by the infallible certainty of the truths of Christ. The things are thus sure, thus clear; and yet you receive not our witness. Multitudes to be unbelievers of that which yet (so cogent are the motives of credibility) they cannot disbelieve!