1 John 4:1

Beloved, believe not every spirit
The apostle having mentioned the word "spirit" in the latter part of the preceding chapter, takes an occasion from thence to return to what he had been suggesting in the "second" chapter, concerning the many antichrists that then were, and whom he points out, and here cautions against. By "every spirit" he means, either every doctrine that is pretended to come from the Spirit of God, or every teacher, who professes to be qualified and sent by him, and to have his light, knowledge, and doctrine from him. Every true minister of the Gospel has the Spirit, and the gifts of the Spirit, more or less, to qualify him for his work; he is separated, and called to it by him, and receives his spiritual light find knowledge from him; it is he that teaches him sound doctrine, and leads him into all truth, as it is in Jesus, and brings every necessary truth to his remembrance; and who succeeds his ministrations to the good of souls: but there are some who call themselves the ministers of the Gospel, who, though they may have some natural abilities, and a share of human learning, and a notional knowledge of things, yet have never received either grace or gifts from the Spirit; nor have they been ever called by him; nor are their ministrations according to that divine word which is inspired by him, nor attended with his demonstration and power; wherefore, though some professing to have the Spirit of Christ are to be believed, yet not everyone; and though the Spirit is not to be quenched in any, nor prophesying to be despised, yet care should be taken what is heard and received: some persons are so obstinate and incredulous as not to believe anything that is declared, be the evidence what it will; as the Jews would not believe Christ and his apostles, though what they said agreed with Moses and the prophets, and was confirmed by miracles; and others are too credulous; at once receive every teacher, and embrace every upstart doctrine: this they should not do,

but try the spirits whether they are of God;
not by human reason, especially as carnal and unsanctified; for though the doctrines of the Gospel are not contrary to true reason, they are above it, and not to be judged of by it, and are disapproved of and rejected by carnal reason; but by the word of God, which is the standard of all doctrine; and whatever agrees with that is to be received, and what does not should be rejected. And so to do is very commendable, as appears from the instance of the Beraeans, who on this account are said to be more noble than those of Thessalonica, ( Acts 17:11 ) ; and from the commendation of the church at Ephesus, ( Revelation 2:2 ) . And this is what every believer, every private Christian should do; to them it belongs to read and search the Scriptures, and prove all things, and judge for themselves of the truth of doctrine; and to such a probation or trial of the spirits, spiritual light, knowledge, judgment, sense, experience, and divine guidance are necessary, which should be asked of God, and an increase thereof; and all such diligent searchers, and humble inquirers, are capable of making judgment of persons and doctrines, whether they are from the Spirit of God or not, for the Spirit of God never speaks contrary to his word: and the reason why such a trial should be made is,

because many false prophets are gone out into the world:
such who pretended either to a revelation of future things, and to foretell things to come; or rather to a gift of prophesying, or preaching in Christ's name, to be "prophets" and spiritual men, and ministers of the word, but were "false" ones; who either predicted what did not come to pass, or rather preached false doctrine, by corrupting the word, and handling it deceitfully, and so imposed upon and ruined the souls of others, as well as deceived their own: and there were not only one, or two, or a few of these, but "many", as our Lord had foretold, ( Matthew 24:11 Matthew 24:24 ) ; and which makes the reason the stronger for not believing every spirit, but trying them; and the rather, since they were not sent of God, hot called out by his churches, but were "gone out" of themselves; of their own heads, and without any mission from God or man: and "into the world" too; they were in every part of it, and especially where there were any churches of Christ; into which they first crept in privily, and at unawares, but afterwards became public preachers of the word, and then separating from them, set up openly in the world for themselves.