1Jo 4:1
4:1 {1} Beloved, believe not every {a} spirit, but try the
    spirits whether they are of God: because many false prophets
    are gone out into the world.

 (1) Taking occasion by the name of the Spirit, lest love and
     charity should be separated from the worship of God, which
     chiefly depends on his true knowledge, he returns to that
     which he spoke of in the second chapter concerning the
     taking heed of antichrists: He will have us here take heed
     of two things, the one is, that seeing there are many false
     prophets, we should not trust every man: the other is, that
     because many men teach false things, we should not
     therefore believe any. We must then observe, that we may be
     able to discern the spirits of God which are to be
     followed, from impure spirits which are to be avoided.
    (a) This is spoken by metonymy and it is as if he had said,
        Believe not every one who says that he has a gift of the
        Holy Spirit to do the office of a prophet.

1Jo 4:2
4:2 {2} Hereby know ye the Spirit of God: {b} Every spirit that
    confesseth that {c} Jesus Christ is come in the {d} flesh is
    of God:

 (2) He gives a certain and perpetual rule to know the doctrine
     of antichrist, that is, if either the divine or human
     nature of Christ, or the true uniting of them together is
     denied: or if the least jot that may be, be detracted from
     his office who is our only king, prophet and everlasting
     high priest.
    (b) He speaks simply of the doctrine, and not of the person.
    (c) The true Messiah.
    (d) Is true man.

1Jo 4:4
4:4 {3} Ye are of God, little children, and have overcome them:
    because greater is he that is in you, than he that is in the
    world.

 (3) He comforts the elect with a most sure hope of victory: but
     yet so, that he teaches them that they fight not with their
     own power, but with the virtue and power of God.

1Jo 4:5
4:5 {4} They are of the world: therefore speak they of the
    world, and the world heareth them.

 (4) He brings a reason why the world receives these teachers
     more willingly than the true: that is, because they speak
     nothing but that which is worldly: which is another note
     also to know the doctrine of antichrist by.

1Jo 4:6
4:6 {5} We are of God: he that knoweth God heareth us; he that
    is not of God heareth not us. Hereby know we the {e} spirit
    of truth, and the spirit of error.

 (5) He testifies to them that his doctrine and the doctrine of
     his companions, is the assured word of God which of necessity
     we have boldly to set against all the mouths of the whole
     world, and thereby discern the truth from falsehood.
    (e) True prophets, against whom are false prophets, that is,
        those who err and lead others into error.

1Jo 4:7
4:7 {6} Beloved, let us love one another: {7} for love is of
    God; and every one that loveth is born of God, and knoweth
    God.

 (6) He returns to the commending of brotherly love and charity.
 (7) The first reason: because it is a very divine thing, and
     therefore very fitting for the sons of God: so that whoever
     is missing it cannot be said to know God correctly.

1Jo 4:8
4:8 He that loveth not knoweth not God; {8} for God is love.

 (8) A confirmation: for it is the nature of God to love men, of
     which we have a most manifest proof above all other, in
     that of his only free and infinite good will towards us his
     enemies, he delivered to death, not a common man, but his
     own Son, indeed his only begotten Son, to the end that we
     being reconciled through his blood might be partakers in his
     everlasting glory.

1Jo 4:11
4:11 {9} Beloved, if God so loved us, we ought also to love one
     another.

 (9) An other reason by comparison: if God so loved us, shall
     not we his children love one another?

1Jo 4:12
4:12 {10} No man hath seen God at any time. If we love one
     another, God dwelleth in us, and his love is {g} perfected
     in us.

 (10) A third reason: Because God is invisible, therefore by
      this effect of his Spirit, that is, by charity, he is
      understood to be not out of us, but united with us and in
      us, in whom he is so effectually working.
     (g) Is surely in us indeed, and in truth.

1Jo 4:14
4:14 {11} And we have seen and do testify that the Father sent
     the Son [to be] the Saviour of the world.

 (11) He underlays this charity with another foundation, that
      is, faith in Jesus, which joins us indeed with him, even
      as charity witnesses that we are joined with him.
      Furthermore he testifies of Christ, as who had seen him
      with his eyes.

1Jo 4:15
4:15 Whosoever shall {h} confess that Jesus is the Son of God,
     God dwelleth in him, and he in God.

     (h) With such a confession as comes from true faith, and is
         accompanied with love, so that there is an agreement of
         all things.

1Jo 4:16
4:16 And we have known and believed the love that God hath to
     us.  {12} God is love; and he that dwelleth in love
     dwelleth in God, and God in him.

 (12) A fourth reason: God is the fountain and wellspring of
      charity indeed charity itself: therefore whoever abides in
      it, has God with him.

1Jo 4:17
4:17 {13} Herein is our love made perfect, that we may have
     boldness in the day of judgment: because {i} as he is, so
     are we in this world.

 (13) Again (as before) he commends love, seeing that by our
      agreement with God in this thing, we have a sure testimony
      of our adoption, it comes to pass by this that without
      fear we look for that latter day of judgment, so that
      trembling and torment of conscience is cast out by this
      love.
     (i) This signifies a likeness, not an equality.

1Jo 4:18
4:18 There is no {k} fear in love; but perfect love casteth out
     fear: because fear hath torment. He that feareth is not
     made perfect in love.

 (k) If we understand by love, that we are in God, and God in
     us, that we are sons, and that we know God, and that
     everlasting life is in us: he concludes correctly, that we
     may well gather peace and quietness by this.

1Jo 4:19
4:19 {14} We love him, because he first loved us.

 (14) Lest any man should think that that peace of conscience
      proceeds from our love as the cause, he goes back to the
      fountain, that is, to the free love with which God loves
      us although we deserved and do deserve his wrath. From
      this springs another double charity, which both are tokens
      and witnesses of that first, that is, that we love God who
      loved us first, and then for his sake our neighbours also.

1Jo 4:20
4:20 {15} If a man say, I love God, and hateth his brother, he
     is a liar: {16} for he that loveth not his brother whom he
     hath seen, how can he love God whom he hath not seen?

 (15) As he showed that the love of our neighbour cannot be
      separate from the love with which God loves us because
      this last gives rise to the other: so he denies that the
      other kind of love with which we love God, can be separate
      from the love of our neighbour: of which it follows, that
      they who say they worship God, and yet do not regard their
      neighbours lie shamelessly.
 (16) The first reason taken from comparison: why we cannot hate
      our neighbour and love God, that is, because he that
      cannot love his brother whom he sees, how can he love God
      whom he cannot see?

1Jo 4:21
4:21 {17} And this commandment have we from him, That he who
     loveth God love his brother also.

 (17) A second reason, why God cannot be hated and our neighbour
      loved, because this same lawmaker commanded us both to
      love him and our neighbour.