From the early Church Fathers to now.
6 Patristic · 1 Orthodox
“Whosoever shall confess that Jesus is the Son of God, God abideth in him, and he in God.”
“But "whosoever shall confess that (Jesus) Christ is the Son of God" (not the Father), "God dwelleth in him, and he in God. " We believe not the testimony of God in which He testifies to us of His Son.”
“Nor let the Jews, or philosophers, flatter themselves respecting the Supreme God. He who has not acknowledged the Son has been unable to acknowledge the Father.”
“This needs to be properly understood. God will not dwell in anyone who does not obey his commandments, however much he may confess him with his lips. Some people are confused by the various names of Jesus, because they do not interpret the Scriptures correctly. They think that because he came out of the womb of Mary according to the flesh and was given the name Jesus at that time, he is not to be identified with the eternal Son of God, who did not think it robbery to be considered equal with God. They restrict themselves to the human form which the Word of God assumed, even though the being of the Word was never changed into humanity. To confess the one Lord Jesus Christ is to confess him as God and man, not as a man only.”
“"Whosoever shall confess that Jesus is the Son of God, God dwelleth in him and he in God." Now we may say it in not many words; "Whosoever shall confess;" not in word but in deed, not with tongue but with the life. For many confess in words, but in deeds deny.”
“Whoever confesses that Jesus is the Son of God, etc. He speaks of the perfect confession of the heart, which can neither be corrupted by the deceit of heretics who wrongly persuade, nor be shattered by the tortures of pagan persecutors, nor falter by the examples of fleshly brothers, nor waver by the sluggishness of one's own weakness. For there are those who even deny by words that Jesus is the Son of God, of which many are reported to have been at that very time when John wrote this. Likewise, there are those who confess in words, but deny in actions. Hence it is well stated now: Whoever confesses that Jesus is the Son of God, God abides in him, and he in God, he said a little above: If we love one another, God abides in us, surely insinuating that whoever has love for his brothers, he truly testifies that Jesus is the Son of God.”
“This refers to what was said a little above (v. 2): every spirit that confesses the Lord Jesus, who has come in the flesh. The apostle has sufficiently proved that believers are children of God and that God abides in them; and he proved this by love for one another, because the Holy Spirit was given to them. After this he returns to the aforementioned discourse and says: whoever confesses that Jesus is the Son of God, God abides in him, because, as was said above, every spirit that confesses Jesus Christ, who has come in the flesh, is from God.”
“Whoever confesses that Jesus is the Son of God, God abides in him, and he in God. And we have known and believed the love that God has for us. God is love, and he who abides in love abides in God, and God in him. This refers to what has been said a little earlier, namely that every spirit that confesses Jesus Christ has come in the flesh is from God. (1 Jn. 4:2) For John has sufficiently demonstrated that they are children of God and that God abides in them: this has been demonstrated through great love, which confirms that the Holy Spirit or spiritual gifts have been given to them: again, he refers to those words and says: "Whoever confesses that Jesus is the Son of God, God abides in him;" saying something of this kind: John said above, Everyone who confesses that Jesus Christ has come in the flesh is from God (1 Jn. 4:2): furthermore, in the course of the conversation, something else was revealed, and therefore he proposed this: that those who confess these things also have the Spirit abiding in themselves, or God and his spiritual gifts, and they themselves abide in God. And this we do not say lightly, but with firm knowledge and faith through mutual love.”
The in-app commentary runs from the Fathers to the early-modern record, then stops — that's where the public-domain sources end, not where the reading does. For the modern reading, follow the sources directly.