John Calvin on 1 John 2:17

17 And the world passeth away As there is nothing in the world but what is fading, and as it were for a moment, he hence concludes that they who seek their happiness from it, make a wretched and miserable provision for themselves, especially when God calls us to the ineffable glory of eternal life; as though he had said, “The true happiness which God offers to his children, is eternal; it is then a shameful thing for us to be entangled with the world, which with all its benefits will soon vanish away.” I take lust here metonymically, as signifying what is desired or coveted, or what captivates the desires of men. The meaning is, that what is most precious in the world and deemed especially desirable, is nothing but a shadowy phantom.

By saying that they who do the will of God shall abide for ever, or perpetually, he means that they who seek God shall be perpetually blessed. Were any one to object and say, that no one doeth what God commands, the obvious answer is, that what is spoken of here is not the perfect keeping of the law, but the obedience of faith, which, however imperfect it may be, is yet approved by God. The will of God is first made known to us in the law; but as no one satisfies the law, no happiness can be hoped from it. But Christ comes to meet the despairing with new aid, who not only regenerates us by his Spirit that we may obey God, but makes also that our endeavor, such as it is, should obtain the praise of perfect righteousness.

1 John 2:18-19

18. Little children, it is the last time: and as ye have heard that antichrist shall come, even now are there many antichrists; whereby we know that it is the last time.

18. Filioli, novissima hora est; et sicut audistis quod Antichristus venturus sit, etiam nunc Antichristi multi coeperunt esse: unde scimus esse novissimam horam.

19. They went out from us, but they were not of us; for if they had been of us, they would no doubt have continued with us; but they went out, that they might be made manifest that they were not all of us.

19. Ex nobis egressi sunt, sed non erant ex nobis; nam si fuissent ex nobis, permansissent utique nobiscum; sed ut manifesti fierent quod non erant omnes ex nobis.