1 John 1:20

And we know that the Son of God has come, &c. S. Ambrose (lib. 1 de Fid. c. 7) reads, hath appeared. The Apostle now explains what he had said, that we are of God, and therefore have overcome the world and the wicked one; namely, that this has been done and is being done through Christ. God for this very end sent His Son into the world in our flesh, that by His Divine doctrine He might give us the sense and the knowledge of heavenly things, that forsaking our idols, and being freed from sin, the devil, and the world, as from false gods, we might know the true God, and might, by faith, hope, and charity, be incorporated into Christ His Son and His Church, and so be endowed by Him with the life of grace and everlasting glory. For He is the very true God, and the true, uncreated, everlasting Life itself

And hath given us sense. (Vulg.). Instead of sense the Greek has διανοίαν, which the Syriac lenders understanding, i.e., illumination of the mind, divine knowledge. Vatablus translates, mind.

That we may know the true God, i.e. the Father.

And may be in His true Son. (Vulg.). The Greek, the Syriac, and S. Athanasius (Orat. Deus de Deo) read, And may be in Himself the True, namely in His Son Jesus Christ. By this is meant that the Son is of the same substance with the Father, because He is True and the Truth essentially; namely, true God, even as the Father.

In these few words S. John gives as it were a compendium of his whole epistle, and of the Christian faith and creed. He marks its two chief mysteries; namely, the oneness of Substance of the Father and the Son, and the Incarnation of Christ. Wherefore Bede saith, "What can be plainer than these words? What more sweet? What stronger utterances can there be against all heresies?" And S. Athanasius (Disp. c. Arius) says, "This is the very thing which Arius asked for, a written demonstration of the Godhead of the Son." And S. Cyril (12 Thesau. c. 13) says, "If He (the Son) is true God, this must be as to His Substance, not participatively, as a creature. For He who is true God is God by nature." And S. Ambrose (lib. 1 de fide, cap. ult.) says, "If He be true God, surely He was not created, having nothing fallacious or unreal, nothing confused or dissimilar." And in the 8th chap. he intimates that the expressions in the Nicene Creed, "God of God, Light of Liaht, very God of very God," &c., are drawn from this verse. And S. Jerome says, "If He were not true (God), He would be like an idol."

This is the true God. Erasmus, Arianising after his manner, says, and twisting, as he does many passages of Scripture which speak of the Divinity of the Son, perverts this passage also. He, he says, viz., the true God that is, the Father, not the Son is true God. But this would be tautology. For who does not know that the true God is true God? Wherefore the pronoun He, or This (hic), does not refer to the words true God, which preceded, but refers to the true Son of God. We may add that in S. John's age, just as in later ages, no one doubted about the Divinity of the Father, but many doubted about, yea denied, the Godhead of the Son. It is this therefore which S. John labours to maintain. Listen to S. Athanasius on the words, " things are delivered to Me of My Father :" This Father is Light, the Son is a beam and ray of Light, the Father is true Light and true God. The Son is true God. For so it is written by S. John, We are in Jesus Christ the True : He is the true God and eternal Life."