Each decade of years is here looked upon as a providentially fixed duration of time. The poet intended to retire from the work of imaginative poetry when his life should draw on towards sixty years of age.
Ver. 19. "It doth not appear, nor is it probable, that these antichrists, when gone out from the Apostles, did still pretend to the orthodox faith; and therefore no need for the Apostle to make any provision against it. Nay, it is plainly intimated by the following discourse, that these antichrists being gone forth, did set themselves expressly, directly, against the orthodox, denying that Jesus, whom they did profess, to be the Christ; and therefore the design of this clause is most rationally conceived to be the prevention of that scandal which their horrid apostasy might give to weak Christians; nor could anything more effectually prevent or remove it, than to let them know that these antichristian apostates were never true stars in the firmament of the Church, but only blazing comets, as their falling away did evidently demonstrate."—Dean Hardy, 309.
Ver. 19. To use the words of a once famous controversial divine, they may be said to be "of the Church presumptively in their own, and others' opinion, but not really." (Spalat., lib. vii., 10, cf. on the whole subject, St. Aug. Lib. de Bono. Persev., viii.)
"Let no one count that the good can go forth from the Church; the wind cannot carry away the wheat, nor the storm overthrow the solidly rooted tree. The light chaff is tossed by the wind, the weak trees go down before the blast. 'They went out from us, but they were not of us.'"—S. Cyp., B. de Simplic.
Ver. 24. Ye shall abide in the Son, and in the Father.] "If it be asked why the Son is put before the Father, the answer is well returned. Because the Apostle had just before inveighed against those who, though they pretended to acknowledge the Father, yet deny the Son. Though withal there may besides be a double reason assigned: the one to insinuate that the Son is not less than the Father, but that they are equal in essence and dignity. Upon this account most probable it is that the apostolical benediction beginneth with 'The grace of our Lord Jesus Christ,' and then followeth 'the love of God the Father.' The other, because, as Beda well glosseth, No man cometh in, or continueth in, the Father but by the Son, who saith of Himself, 'I am the way, the truth, and the life.'
"To draw it up, lo, here Eximia laus doctrinæ, an high commendation of evangelical doctrine, that it leads up to Christ, and by Him to the Father. The water riseth as high as the spring from whence it floweth. No wonder if the gospel, which cometh from God through Christ, lead us back again through Christ to God; and as by hearing and believing this doctrine we are united to, so by adhering to, and persevering in it, we continue in, the Son and the Father. Suitable to this is that promise of our blessed Saviour, John xiv. 23, 'If any man love Me he will keep My word, and My Father will love him, and we will come to him and make our abode with him.'"—Dean Hardy, 350.
Ver. 27. The connection of the whole section is well traced by the old divine, whose commentary closes a little below.
"If you compare these three with the eight foregoing verses, you shall find them to be a summary repetition of what is there more largely delivered. There are three hinges upon which the precedent discourse turneth, namely, the peril of antichristian doctrine, the benefit of the Spirit's unction, the duty of perseverance in the Christian faith; and these three are inculcated in these verses. Indeed, where the danger is very great, the admonition cannot be too frequent. When the benefit is of singular advantage, it would be often considered, and a duty which must be performed cannot be too much pressed. No wonder if St. John proposed them in this gemination to our second thoughts. And yet it is not a naked repetition neither, but such as hath a variation and amplification in every particular. The duty is reinforced at the eight-and-twentieth verse, but in another phrase, of 'abiding in Christ,' and with a new motive, drawn from the second coming of Christ. The benefit is reiterated, and much amplified, in the seven-and-twentieth verse, as to its excellency and energy. Finally, the danger is repeated, but with another description of those by whom they were in danger; whilst as before he had called them antichrists for their enmity against Christ, so here, for their malignity against Christians, he calleth them seducers: 'These things have I written to you concerning them that seduce you,' etc."—Dean Hardy, 357.