Here we have,

I.A recapitulation of the privileges and advantages of sound Christian believers. 1. They are secured against sin, against the fulness of its dominion or the fulness of its guilt: We know that whosoever is born of God (and the believer in Christ is born of God, Jo1 5:1) sinneth not (Jo1 5:18), sinneth not with that fulness of heart and spirit that the unregenerate do (as was said Jo1 3:6, Jo1 3:9), and consequently not with that fulness of guilt that attends the sins of others; and so he is secured against that sin which is unavoidably unto death, or which infallibly binds the sinner over unto the wages of eternal death; the new nature, and the inhabitation of the divine Spirit thereby, prevent the admission of such unpardonable sin. 2. They are fortified against the devil's destructive attempts: He that is begotten of God keepeth himself, that is, is enabled to guard himself, and the wicked one toucheth him not (Jo1 5:18), that is, that the wicked one may not touch him, namely, to death. It seems not to be barely a narration of the duty or the practice of the regenerate; but an indication of their power by virtue of their regeneration. They are thereby prepared and principled against the fatal touches, the sting, of the wicked one; he touches not their souls, to infuse his venom there a he does in others, or to expel that regenerative principle which is an antidote to his poison, or to induce them to that sin which by the gospel constitution conveys an indissoluble obligation to eternal death. He may prevail too far with them, to draw them to some acts of sin; but it seems to be the design of the apostle to assert that their regeneration secures them from such assaults of the devil as will bring them into the same case and actual condemnation with the devil. 3. they are on God's side and interest, in opposition to the state of the world: And we know that we are of God, and the whole world lieth in wickedness, Jo1 5:19. Mankind are divided into two great parties of dominions, that which belongs to God and that which belongs to wickedness or to the wicked one. The Christian believers belong to God. They are of God, and from him, and to him, and for him. They succeed into the right and room of the ancient Israel of God, of whom it is said, The Lord's people is his portion, his estate in this world; Jacob is the lot of his inheritance, the dividend that has fallen to him by the lot of his own determination (Deu 32:9); while, on the contrary, the whole world, the rest, being by far the major part, lieth in wickedness, in the jaws in the bowels of the wicked one. There are, indeed, were we to consider the individuals, many wicked ones, many wicked spirits, in the heavenly or the ethereal places; but they are united in wicked nature, policy, and principle, and they are united also in one head. there is the prince of the devils and of the diabolical kingdom. There is a head of the malignity and of the malignant world; and he has such sway here that he is called the god of this world. Strange that such a knowing spirit should be so implacably incensed against the Almighty and all his interests, when he cannot but know that it must end in his own overthrow and everlasting damnation! How tremendous is the judgment of God upon that wicked one! May the God of the Christian world continually demolish his dominion in this world, and translate souls into the kingdom of his dear Son! 4. They are enlightened in the knowledge of the true eternal God: "And we know that the Son of God has come, and has given as an understanding, that we may know him that is true, Jo1 5:20. The Son of God has come into our world, and we have seen him, and know him by all the evidence that has already been asserted; he has revealed unto us the true God (as Joh 1:18), and he has opened our minds too to understand that revelation, given us an internal light in our understandings, whereby we may discern the glories of the true God; and we are assured that it is the true God that he hath discovered to us. He is infinitely superior in purity, power, and perfection, to all the gods of the Gentiles. He has all the excellences, beauties, and riches, of the living and true God. It is the same God that, according to Moses's account, made the heavens and the earth, the same who took our fathers and patriarchs into peculiar covenant with himself, the same who brought our ancestors out of Egypt, who gave us the fiery law upon mount Sinai, who gave us his holy oracles, promised the call and conversion of the Gentiles. By his counsels and works, by his love and grace, by his terrors and judgments, we know that he, and he alone, in the fulness of his being, is the living and true God." It is a great happiness to know the true God, to know him in Christ; it is eternal lie, Joh 17:3. It is the glory of the Christian revelation that it gives the best account of the true God, and administers the best eye-salve for our discerning the living and true God. 5. They have a happy union with God and his Son: "And we are in him that is true, even (or and) in his Son Jesus Christ, Jo1 5:20. The Son leads us to the Father, and we are in both, in the love and favour of both, in covenant and federal alliance with both, in spiritual conjunction with both by the inhabitation and operation of their Spirit: and, that you may know how great a dignity and felicity this is, you must remember that this true one is the true God and eternal life" or rather (as it should seem a more natural construction), "This same Son of God is himself also the true God and eternal life" (Joh 1:1, and here, Jo1 1:2), "so that in union with either, much more with both, we are united to the true God and eternal life." Then we have,

II.The apostle's concluding monition: "Little children" (dear children, as it has been interpreted), "keep yourselves from idols, Jo1 5:21. Since you know the true God, and are in him, let your light and love guard you against all that is advanced in opposition to him, or competition with him. Flee from the false gods of the heathen world. They are not comparable to the God whose you are and whom you serve. Adore not your God by statues and images, which share in his worship. Your God is an incomprehensible Spirit, and is disgraced by such sordid representations. Hold no communion with your heathen neighbours in their idolatrous worship. Your God is jealous, and would have you come out, and be separated from among them; mortify the flesh, and be crucified to the world, that they may not usurp the throne of dominion in the heart, which is due only to God. The God whom you have known is he who made you, who redeemed you by his Son, who has sent his gospel to you, who has pardoned your sins, begotten you unto himself by his Spirit, and given you eternal life. Cleave to him in faith, and love, and constant obedience, in opposition to all things that would alienate your mind and heart from God. To this living and true God be glory and dominion for ever and ever. Amen."

We know that we are of God - Have the fullest proof of the truth of Christianity, and of our own reconciliation to God through the death of his Son.

The whole world lieth in wickedness - Εν τῳ πονηρῳ κειται· Lieth in the wicked one - is embraced in the arms of the devil, where it lies fast asleep and carnally secure, deriving its heat and power from its infernal fosterer. What a truly awful state! And do not the actions, tempers, propensities, opinions and maxims of all worldly men prove and illustrate this? "In this short expression," says Mr. Wesley, "the horrible state of the world is painted in the most lively colors; a comment on which we have in the actions, conversations, contracts, quarrels and friendships of worldly men." Yes, their Actions are opposed to the law of God; their Conversations shallow, simulous, and false; their Contracts forced, interested, and deceitful; their Quarrels puerile, ridiculous, and ferocious; and their Friendships hollow, insincere, capricious, and fickle: - all, all the effect of their lying in the arms of the wicked one; for thus they become instinct with his own spirit: and because they are of their father the devil, therefore his lusts they will do.

And we know that we are of God,.... The sons of God, and regenerated by him; this is known by the Spirit of God, which witnesses to the spirits of the saints that they are the children of God; and by the fruits and effects of regenerating grace, as love to the brethren, and the like:

and the whole world lies in wickedness; that is, the men of the world, the greater part of the inhabitants of it, who are as they were when they came into it, not being born of God; these are addicted to sin and, wickedness; the bias of their minds is to it, they are set upon it, and give themselves up to it, are immersed in it, and are under the power of it: or "in the wicked one"; Satan, the god of this world; they are under his influence, and led according to his will, and they are governed by him, and are at his beck and command; and this is known, by sad experience, it is easy of observation;

"And cannot comprehend the things that are promised to the righteous in time to come: for this world is full of unrighteousness and infirmities.'' (2 Esdras 4:27)

world lieth in wickedness--rather, "lieth in the wicked one," as the Greek is translated in Jo1 5:18; Jo1 2:13-14; compare Jo1 4:4; Joh 17:14-15. The world lieth in the power of, and abiding in, the wicked one, as the resting-place and lord of his slaves; compare "abideth in death," Jo1 3:14; contrast Jo1 5:20, "we are in Him that is true." While the believer has been delivered out of his power, the whole world lieth helpless and motionless still in it, just as it was; including the wise, great, respectable, and all who are not by vital union in Christ.