1. Beloved—the affectionate address wherewith he calls their attention, as to an important subject.
every spirit—which presents itself in the person of a prophet. The Spirit of truth, and the spirit of error, speak by men's spirits as their organs. There is but one Spirit of truth, and one spirit of Antichrist.
try—by the tests (1 John 4:2; 1 John 4:3). All believers are to do so: not merely ecclesiastics. Even an angel's message should be tested by the word of God: much more men's teachings, however holy the teachers may seem.
because, c.—the reason why we must "try," or test the spirits.
many false prophets—not "prophets" in the sense "foretellers," but organs of the spirit that inspires them, teaching accordingly either truth or error: "many Antichrists."
are gone out—as if from God.
into the world—said alike of good and bad prophets (1 John 4:3). The world is easily seduced (1 John 4:4 1 John 4:5).

2. Hereby—"Herein."
know . . . the Spirit of God—whether he be, or not, in those teachers professing to be moved by Him.
Every spirit—that is, Every teacher claiming inspiration by the HOLY SPIRIT.
confesseth—The truth is taken for granted as established. Man is required to confess it, that is, in his teaching to profess it openly.
Jesus Christ is come in the flesh—a twofold truth confessed, that Jesus is the Christ, and that He is come (the Greek perfect tense implies not a mere past historical fact, as the aorist would, but also the present continuance of the fact and its blessed effects) in the flesh ("clothed with flesh": not with a mere seeming humanity, as the Docetæ afterwards taught: He therefore was, previously, something far above flesh). His flesh implies His death for us, for only by assuming flesh could He die (for as God He could not), Hebrews 2:9; Hebrews 2:10; Hebrews 2:14; Hebrews 2:16; and His death implies His LOVE for us (Hebrews 2:16). To deny the reality of His flesh is to deny His love, and so cast away the root which produces all true love on the believer's part (1 John 4:9-11; 1 John 4:19). Rome, by the doctrine of the immaculate conception of the Virgin Mary, denies Christ's proper humanity.

3. confesseth not that Jesus Christ is come in the flesh—IRENÆUS [3.8], LUCIFER, ORIGEN, on Matthew 25:14, and Vulgate read, "Every spirit which destroys (sets aside, or does away with) Jesus (Christ)." CYPRIAN and POLYCARP support English Version text. The oldest extant manuscripts, which are, however, centuries after POLYCARP, read, "Every spirit that confesseth not (that is, refuses to confess) Jesus" (in His person, and all His offices and divinity), omitting "is come in the flesh."
ye have heard—from your Christian teachers.
already is it in the world—in the person of the false prophets (Matthew 25:14).

4. Ye—emphatical: YE who confess Jesus: in contrast to "them," the false teachers.
overcome them— (1 John 5:4; 1 John 5:5); instead of being "overcome and brought into (spiritual) bondage" by them (2 Peter 2:19). John 10:8; John 10:5, "the sheep did not hear them": "a stranger will they not follow, but will flee from him: for they know not the voice of strangers."
he that is in you—God, of whom ye are.
he that is in the word—the spirit of Antichrist, the devil, "the prince of this world."

5. of the world—They derive their spirit and teaching from the world, "unregenerate human nature, ruled over and possessed by Satan, the prince of this world" [ALFORD].
speak they of the word—They draw the matter of their conversation from the life, opinions, and feelings of the world.
the world heareth them— (John 15:18; John 15:19). The world loves its own.

6. We—true teachers of Christ: in contrast to them.
are of God—and therefore speak of God: in contrast to "speak they of the world," 1 John 4:5.
knoweth God—as his Father, being a child "of God" (1 John 2:13; 1 John 2:14).
heareth us—Compare 1 John 2:14, "Every one that is of the truth, heareth My voice."
Hereby— (1 John 2:14); by their confessing, or not confessing, Jesus; by the kind of reception given them respectively by those who know God, and by those who are of the world and not of God.
spirit of truth—the Spirit which comes from God and teaches truth.
spirit of error—the spirit which comes from Satan and seduces into error.

7. Resumption of the main theme (1 John 2:29). Love, the sum of righteousness, is the test of our being born of God. Love flows from a sense of God's love to us: compare 1 John 4:9; 1 John 3:16, which 1 John 3:16 resumes; and 1 John 4:13; 1 John 3:24, which similarly 1 John 3:24 resumes. At the same time, 1 John 3:24 is connected with the immediately preceding context, 1 John 3:24 setting forth Christ's incarnation, the great proof of God's love (1 John 4:10).
Beloved—an address appropriate to his subject, "love."
love—All love is from God as its fountain: especially that embodiment of love, God manifest in the flesh. The Father also is love (1 John 4:10). The Holy Ghost sheds love as its first fruit abroad in the heart.
knoweth God—spiritually, experimentally, and habitually.

8. knoweth not—Greek aorist: not only knoweth not now, but never knew, has not once for all known God.
God is love—There is no Greek article to love, but to God; therefore we cannot translate, Love is God. God is fundamentally and essentially LOVE: not merely is loving, for then John's argument would not stand; for the conclusion from the premises then would be this, This man is not loving: God is loving; therefore he knoweth not God IN SO FAR AS GOD IS LOVING; still he might know Him in His other attributes. But when we take love as God's essence, the argument is sound: This man doth not love, and therefore knows not love: God is essentially love, therefore he knows not God.

9. toward us—Greek, "in our case."
sent—Greek, "hath sent."
into the world—a proof against Socinians, that the Son existed before He was "sent into the world." Otherwise, too, He could not have been our life (1 John 4:9), our "propitiation" (1 John 4:10), or our "Saviour" (1 John 4:14). It is the grand proof of God's love, His having sent "His only-begotten Son, that we might live through Him," who is the Life, and who has redeemed our forfeited life; and it is also the grand motive to our mutual love.

10. Herein is love—love in the abstract: love, in its highest ideal, is herein. The love was all on God's side, none on ours.
not that we loved God—though so altogether worthy of love.
he loved us—though so altogether unworthy of love. The Greek aorist expresses, Not that we did any act of love at any time to God, but that He did the act of love to us in sending Christ.

11. God's love to us is the grand motive for our love to one another ().
if—as we all admit as a fact.
we . . . also—as being born of God, and therefore resembling our Father who is love. In proportion as we appreciate God's love to us, we love Him and also the brethren, the children (by regeneration) of the same God, the representatives of the unseen God.

12. God, whom no man hath seen at any time, hath appointed His children as the visible recipients of our outward kindness which flows from love to Himself, "whom not having seen, we love," compare Notes, 1 John 4:11, 1 John 4:11. Thus 1 John 4:12 explains why, instead (in 1 John 4:11) of saying, "If God so loved us, we ought also to love God," he said, "We ought also to love one another."
If we love one another, God dwelleth in us—for God is love; and it must have been from Him dwelling in us that we drew the real love we bear to the brethren (1 John 4:8; 1 John 4:16). John discusses this in 1 John 4:16.
his love—rather, "the love of Him," that is, "to Him" (1 John 4:16), evinced by our love to His representatives, our brethren.
is perfected in us—John discusses this in 1 John 4:16. Compare 1 John 2:5, "is perfected," that is, attains its proper maturity.

13. Hereby—"Herein." The token vouchsafed to us of God's dwelling (Greek, "abide") in us, though we see Him not, is this, that He hath given us "of His Spirit" (1 John 3:24). Where the Spirit of God is, there God is. ONE Spirit dwells in the Church: each believer receives a measure "of" that Spirit in the proportion God thinks fit. Love is His first-fruit (Galatians 5:22). In Jesus alone the Spirit dwelt without measure (Galatians 5:22).

14. And we—primarily, we apostles, Christ's appointed eye-witnesses to testify to the facts concerning Him. The internal evidence of the indwelling Spirit (1 John 4:13) is corroborated by the external evidence of the eye-witnesses to the fact of the Father having "sent His Son to be the Saviour of the world."
seen—Greek, "contemplated," "attentively beheld" (see on 1 John 4:13).
sent—Greek, "hath sent": not an entirely past fact (aorist), but one of which the effects continue (perfect tense).

15. shall confess—once for all: so the Greek aorist means.
that Jesus is the Son of God—and therefore "the Saviour of the world" ().

16. And we—John and his readers (not as 1 John 4:14, the apostles only).
known and believed—True faith, according to John, is a faith of knowledge and experience: true knowledge is a knowledge of faith [LUECKE].
to us—Greek, "in our case" (see on 1 John 4:9).
dwelleth—Greek, "abideth." Compare with this verse, 1 John 4:9.

17, 18. (Compare .)
our love—rather as the Greek, "LOVE (in the abstract, the principle of love [ALFORD]) is made perfect (in its relations) with us." Love dwelling in us advances to its consummation "with us" that is, as it is concerned with us: so Greek. , "showed mercy upon (literally, 'with') her": , the truth "shall be with us for ever."
boldness—"confidence": the same Greek as 1 John 3:21, to which this passage is parallel. The opposite of "fear," 1 John 4:18. Herein is our love perfected, namely, in God dwelling in us, and our dwelling in God (1 John 4:16), involving as its result "that we can have confidence (or boldness) in the day of judgment" (so terrible to all other men, Acts 24:25; Romans 2:16).
because, &c.—The ground of our "confidence" is, "because even as He (Christ) is, we also are in this world" (and He will not, in that day, condemn those who are like Himself), that is, we are righteous as He is righteous, especially in respect to that which is the sum of righteousness, love (Romans 2:16). Christ IS righteous, and love itself, in heaven: so are we, His members, who are still "in this world." Our oneness with Him even now in His exalted position above (Romans 2:16), so that all that belongs to Him of righteousness, &c., belongs to us also by perfect imputation and progressive impartation, is the ground of our love being perfected so that we can have confidence in the day of judgment. We are in, not of, this world.

18. Fear has no place in love. Bold confidence (), based on love, cannot coexist with fear. Love, which, when perfected, gives bold confidence, casts out fear (compare Hebrews 2:14; Hebrews 2:15). The design of Christ's propitiatory death was to deliver from this bondage of fear.
but—"nay" [ALFORD].
fear hath torment—Greek, "punishment." Fear is always revolving in the mind the punishment deserved [ESTIUS]. Fear, by anticipating punishment (through consciousness of deserving it), has it even now, that is, the foretaste of it. Perfect love is incompatible with such a self-punishing fear. Godly fear of offending God is quite distinct from slavish fear of consciously deserved punishment. The latter fear is natural to us all until love casts it out. "Men's states vary: one is without fear and love; another, with fear without love; another, with fear and love; another, without fear with love" [BENGEL].

19. him—omitted in the oldest manuscripts. Translate, We (emphatical: WE on our part) love (in general: love alike Him, and the brethren, and our fellow men), because He (emphatical: answering to "we"; because it was He who) first loved us in sending His Son (Greek aorist of a definite act at a point of time). He was the first to love us: this thought ought to create in us love casting out fear ().

20. loveth not . . . brother whom he hath seen, how can he love God whom he hath not seen—It is easier for us, influenced as we are here by sense, to direct love towards one within the range of our senses than towards One unseen, appreciable only by faith. "Nature is prior to grace; and we by nature love things seen, before we love things unseen" [ESTIUS]. The eyes are our leaders in love. "Seeing is an incentive to love" [OEligCUMENIUS]. If we do not love the brethren, the visible representatives of God, how can we love God, the invisible One, whose children they are? The true ideal of man, lost in Adam, is realized in Christ, in whom God is revealed as He is, and man as he ought to be. Thus, by faith in Christ, we learn to love both the true God, and the true man, and so to love the brethren as bearing His image.
hath seen—and continually sees.

21. Besides the argument () from the common feeling of men, he here adds a stronger one from God's express commandment (). He who loves, will do what the object of his love wishes.
he who loveth God—he who wishes to be regarded by God as loving Him.