The interpretation timeline
2 John 1:9 Douay-Rheims

Whosoever revolteth, and continueth not in the doctrine of Christ, hath not God. He that continueth in the doctrine, the same hath both the Father and the Son.

1771 – 1871 4 witnesses

Post-Reformation

c. 1650 – 1900
1771
A.D.
John Gill Reformed
1697–1771
“Whosoever transgresseth,.... Not the law of God, of which everyone is a transgressors and that daily, in thought, word, or deed; but who passes over the rule and standard of doctrine, the word of God, and will not adhere to that, nor walk according to it, but rejects and despises that rule: and abideth not in the doctrine of Christ; which he received from his Father, and delivered to his apostles, and of which he is the sum and substance; the doctrine which is concerning his person as the Son of God, and as truly God, and the union of the two natures, divine and human, in his one person; and concerning his office, as the Mediator, surety, and messenger of the covenant, and as the prophet, priest, and King of his church; and concerning his incarnation, obedience, sufferings, death, resurrection from the dead, ascension to heaven, session at God's right hand, intercession for his people, and second coming to judgment; concerning peace and pardon by his blood, atonement by his sacrifice, justification by his righteousness, and complete salvation by him: this is , "the doctrine of the King Messiah", or the Messiah's Talmud (h), to use the Jewish phrase, and which agrees with John's. Now, whoever has embraced and professed this doctrine, but errs concerning it, and rejects it, and abides not in it, as Satan abode not in the truth, appears to be of him: hath not God; for his Father, but the devil, the father of lies; he has no true knowledge of God, for there is none but in Christ, whose doctrine such an one has denied; nor has he, nor can he, have communion with him, nor any interest in him. He that abideth in the doctrine of Christ; as he hath received and professed it; neither can anything remove him from it, not the arguments of false teachers, nor the reproaches and persecutions of men, or the snares and allurements of the world: he hath both the Father and the Son; he has an interest in them both, and has knowledge of each of them, and fellowship with them. The Alexandrian copy and the Vulgate Latin version leave out the phrase, "of Christ", in the preceding clause, and only read, "in the doctrine"; and the Syriac version, "in his doctrine"; the sense is the same. (h) Bereshit Rabba, sect. 98. fol. 85. 3.”
Source
1832
A.D.
Adam Clarke Methodist
1762–1832
“Whosoever transgresseth - Παραβαινων· He who passes over the sacred enclosure, or goes beyond the prescribed limits; and abideth not in the doctrine - does not remain within these holy limits, but indulges himself either in excesses of action or passion; hath not God for his Father, nor the love of God in his heart. Hath both the father and the Son - He who abideth in the doctrine of Christ, his body is a temple of the Holy Trinity, and he has communion with the Father as his Father, and with the Son as his Savior and Redeemer.”
Source
1871
A.D.
1871
“The loss (Jo2 1:8) meant is here explained: the not having God, which results from abiding not in the doctrine of Christ. transgresseth--The oldest manuscripts and versions read, "Every one who takes the lead"; literally, "goes," or "leads on before"; compare Joh 10:4, "He goeth before them" (not the same Greek). Compare Jo3 1:9, "Loveth to have the pre-eminence." hath not God-- (Jo1 2:23; Jo1 5:15). The second "of Christ" is omitted in the oldest manuscripts, but is understood in the sense. He--emphatical: He and He alone.”
Source

Undated

date unknown
date
unknown
Glossa Ordinaria Medieval
“And abideth not. If anyone separates himself from the divine teaching, so as to be outside the right faith and the keeping of God's commandments, he separates himself from God, that he may not have God. Through the active and the contemplative life, he who is the Creator of all becomes the God of a man by manifesting himself to him. He that abideth. He abides in the gospel teaching who thinks and acts according to it; he separates himself from it who thinks and acts otherwise.”
Source
Modern · 1953 →

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.