Gr. kosmos (see on ch. 2:15), here meaning the world as an orderly arrangement of things or people. There does not appear to be the same contrast drawn between the church and the world as in ch. 2:15-17, for the false teachers were operating within as well as without the church.
Are gone out.
Or, “have gone out,” though the influence of their going still makes itself felt. It would also appear that the writer is using the verb “to go out” in a different sense from that employed in ch. 2:19 (see comment there), where apostasy is implied. Here he is merely stating the fact of the appearing of false prophets. For other NT evidence that false prophets were active during John’s day see Acts 13:6; Rev. 2:2.
False prophets.
See on Matt. 24:11, 24-26; cf. on ch. 7:15. Here John is obviously referring to false teachers who may be identified with, or at least associated with, the antichrists mentioned in ch. 2:18-22, and the false apostles of Rev. 2:2.
Because.
John clearly states the reason for his counsel, and appeals to facts with which his readers are well acquainted.
Of God.
Literally, “out of God” (cf. ch. 3:10), that is, proceeding from God.
Try.
Gr. dokimazō (see on Rom. 2:18; Phil. 1:10; and for the related word dokimē see on Rom. 5:4; 2 Cor. 9:13). God does not expect the Christian to be gullible; indeed, He bestows on the church the gift of distinguishing between true and false spirits (see on 1 Cor. 12:10). The messages of teachers who make the claim of being accredited by God should be tested by the Word of God. The Bereans gladly listened to Paul, but they studied the Scriptures to see whether he had been teaching truth (see on Acts 17:11). Paul advised his other converts to do similarly (see on 1 Thess. 5:21). It is the duty of each believer to apply to everything that he reads and hears the test of the inspired writings of prophets and apostles. Only so can the church resist the encroachments of false doctrine; only so can each believer have his faith based upon God and not men (1 Peter 3:15).
Spirit.
The apostle bids his hearers to be critical rather than credulous, and not to accept every spiritual activity as coming from God. From this it would appear that they had come under the ministry of men who claimed divine authority for teachings that were really false. The apostle, as a good pastor, warns his flock against specious deception. The nature of the deception is revealed in v. 3.
Believe not.
Or, “stop believing,” as the Greek may be rendered. Thus rendered, the implication is that many were giving heed to various spirits.