5:19 {18} [And] we know that we are of God, and the whole world lieth in wickedness.
(18) Every man must particularly apply to himself the general promises, that we may certainly persuade ourselves, that whereas all the world is by nature lost, we are freely made the sons of God, by the sending of Jesus Christ his son to us, of whom we are enlightened with the knowledge of the true God and everlasting life.
5:19 We know that we are of God. The church is God's temple in which he dwells, and around it the world of wickedness.
5:19 We know that we are children of God - By the witness and the fruit of his Spirit, 1John 3:24. But the whole world - All who have not his Spirit, not only is touched by him, but by idolatry, fraud, violence lasciviousness, impiety, all manner of wickedness. Lieth in the wicked one - Void of life, void of sense. In this short expression the horrible state of the world is painted in the most lively colours; a comment on which we have in the actions, conversations, contracts, quarrels, and friendships of worldly men.
5:18-21 All mankind are divided into two parties or dominions; that which belongs to God, and that which belongs to the wicked one. True believers belong to God: they are of God, and from him, and to him, and for him; while the rest, by far the greater number, are in the power of the wicked one; they do his works, and support his cause. This general declaration includes all unbelievers, whatever their profession, station, or situation, or by whatever name they may be called. The Son leads believers to the Father, and they are in the love and favour of both; in union with both, by the indwelling and working of the Holy Spirit. Happy are those to whom it is given to know that the Son of God is come, and to have a heart to trust in and rely on him that is true! May this be our privilege; we shall thus be kept from all idols and false doctrines, and from the idolatrous love of worldly objects, and be kept by the power of God, through faith, unto eternal salvation. To this living and true God, be glory and dominion for ever and ever. Amen.