On the problems with the Greek grammar
J P Lange, Commentary
"The only question is, whether, in the next clause, τοῦ μεγάλου θεοῦ καὶ σωτῆρος ἡμῶν Ἰησοῦ Χριστοῦ , one independent subject is to be understood [so that it shall read, of our great Gad and Saviour Jesus Christ.—D.], or whether, with most [or rather several—they hardly appear to be the majority.—D.] recent interpreters, it should be rendered, “the appearing of the glory of the great God, and of our Saviour Jesus Christ.” For our part, we decide in favor of the first, and believe he words may, should, and must be understood as giving the name “great God” not to the Father, but to the Saviour Jesus Christ. On purely philological grounds, the position of Bengel will hardly be questioned: “It may be referred to Christ.” Even Winer, § 11, does not deny that σωτῆρος ἡμῶν may be regarded, consistently with grammar, as a second predicate depending upon the article τοῦ. The only ground on which he feels obliged to prefer the other view, adopted by De Wette, Huther, and others, is the doctrinal opinion, derived from the writings of Paul, that this Apostle could not have styled Christ the great God. But in view of 1Ti 3:15-16; Rom 9:5; Col 1:15-20, and other passages, we cannot regard this objection as valid. Equally arbitrary with the position that Paul regarded Christ as a mere man, and nothing more, is the Arian view, that Paul did not recognize Christ as God, yea, as μέγας θεός. Whoever will simply read and translate the words without doctrinal prejudice, will have as little hesitation in referring them to one and the same subject, as in understanding, e.g., in 2Pe 1:11, the words βασιλείαν τοῦ κυρίου ἡμῶν καὶ σωτῆρος Ἰησοῦ Χριστοῦ, as relating to the same subject. He, who is there called κύριος (Lord), is here called μέγας θεός (the great God); as is clear also from the fact that Paul ascribes an “appearing” to the Son (comp. 1Ti 6:14; 2Ti 4:1; 2Ti 4:8), but not to the Father, who is “invisible.” Taking all things into the account, we believe that the sense of the words, and the connection, speak decidedly in favor of one and the same subject (Christ). We cannot, therefore, but regard the use which the Church fathers very early made of this passage as a weapon against the Arians as entirely legitimate. [Ellicott has come to the same result with Dr. Van Oosterzee, which is that also of Calvin, Matthies, Usteri, Wiesinger, Tholuck, and Ebrard. He says: “It must be candidly avowed that it is very doubtful whether, on the grammatical principle last alluded to (in respect to two substantives closely united, and under the vinculum of a common article), the interpretation of this passage can be fully settled; see Winer, § 18, 5 Obs., p. 148. There is a presumption in favor of the adopted interpretation, but, on account of the (defining) genitive ἡμῶν (Winer, p. 142), nothing more"
Expositor's Greek Testament
"On the whole, then, we decide in favour of the R.V.m. in the rendering of this passage, appearing of the glory of the great God and our Saviour Jesus Christ. The grammatical argument—“the identity of reference of two substantives when under the vinculum of a common article”—is too slender to bear much weight, especially when we take into consideration not only the general neglect of the article in these epistles but the omission of it before σωτήρ in 1Ti 1:1; 1Ti 4:10. Ellicott says that “μεγάλου would seem uncalled for if applied to the Father”. To this it may be answered that (a) the epithet is not otiose here; as marking the majesty of God the Father it is parallel to the ὃς ἔδωκεν ἑαυτὸν, κ.τ.λ., which recalls the self-sacrificing love of the Son; both constituting the double appeal—to fear and to love—of the Judgment to come. (b) Again, St. Paul is nowhere more emphatic in his lofty language about God the Father than in these epistles; see 1Ti 1:17; 1Ti 6:15-16."
William Mounce in the Word Bible Commentary, has a very long note on the Greek grammar, which can be used for either one or two Persons. It is too long to add here.
