1Jo 3:1
3:1 Behold, {1} {a} what manner of love the Father hath bestowed
    upon us, that we should be {b} called the sons of God: {2}
    therefore the world knoweth us not, because it knew him not.

 (1) He begins to declare this agreement of the Father and the
     Son, at the highest cause, that is, at that free love of
     God towards us, with which he so loves us, that also he
     adopts us to be his children.
    (a) What a gift of how great love.
    (b) That we should be the sons of God, and so, that all the
        world may see that we are so.
 (2) Before he declares this adoption, he says two things: the
     one, that this so great a dignity, is not to be esteemed
     according to the judgment of the flesh, because it is
     unknown to the world, for the world knows not God the
     Father himself.

1Jo 3:2
3:2 {3} Beloved, now are we the sons of God, and it doth not yet
    appear what we shall be: but we know that, when he shall
    appear, we shall be {c} like him; for we shall see him {d}
    as he is.

 (3) The other: This dignity is not fully revealed to us
     ourselves, much less to strangers, but we are sure of the
     accomplishment of it, in as much as we shall be like the
     Son of God himself and shall enjoy his sight indeed, such
     as he is now, but yet this is deferred until his next
     coming.
    (c) Like, but not equal.
    (d) For now we see as in a glass  1Co 13:12 

1Jo 3:3
3:3 {4} And every man that hath this hope in him purifieth
    himself, even {e} as he is pure.

 (4) Now he describes this adoption (the glory which as yet
     consists in hope) by the effect that is, because whoever is
     made the Son of God, endeavours to resemble the Father in
     purity.
    (e) This word signifies a likeness, but not an equality.

1Jo 3:4
3:4 {5} Whosoever {f} committeth sin transgresseth also the law:
    for {g} sin is the transgression of the law.

 (5) The rule of this purity can from no where else be taken but
     from the law of God, the transgression of which is called
     sin.
    (f) Does not give himself to pureness.
    (g) A short definition of sin.

1Jo 3:5
3:5 {6} And ye know that he was manifested to take away our
    sins; and in him is no sin.

 (6) An argument taken from the material cause of our salvation:
     Christ in himself is most pure, and he came to take away
     our sins, by sanctifying us with the Holy Spirit, therefore
     whoever is truly a partaker of Christ, does not give
     himself to sin, and on the contrary, he that gives himself
     to sin does not know Christ.

1Jo 3:6
3:6 Whosoever abideth in him sinneth not: whosoever {h} sinneth
    hath not seen him, neither known him.

    (h) He is said to sin, that does not give himself to purity,
        and in him sin reigns: but sin is said to dwell in the
        faithful, and not to reign in them.

1Jo 3:7
3:7 {7} Little children, let no man deceive you: he that doeth
    righteousness is righteous, even as he is righteous.

 (7) Another argument of things joined together: He that lives
     justly, is just, and resembles Christ that is just, and by
     that is known to be the Son of God.

1Jo 3:8
3:8 {8} He that committeth sin is of the {i} devil; for the
    devil {k} sinneth from the {l} beginning.  For this purpose
    the Son of God was manifested, that he might destroy the
    works of the devil.

 (8) An argument taken by contrast: the devil is the author of
     sin, and therefore he is that serves sin is of the devil,
     or is ruled by the inspiration of the devil: and if he is
     the devil's son, then is he not God's son: for the devil
     and God are so contrary to one another that the Son of God
     was sent to destroy the works of the devil.  Therefore on
     the other side, whoever resists sin, is the son of God,
     being born again of his Spirit as of new seed, in so much,
     that by necessity he is now delivered from the slavery of
     sin.
    (i) Resembles the devil, as the child does the father, and
        is governed by his Spirit.
    (k) He says not "sinned" but "sins" for he does nothing else
        but sin.
    (l) From the very beginning of the world.

1Jo 3:9
3:9 Whosoever is born of God doth not commit sin; for his {m}
    seed remaineth in him: and he cannot sin, because he is born
    of God.

    (m) The Holy Spirit is so called by the effect he works,
        because by his power and mighty working, as it were by
        seed, we are made new men.

1Jo 3:10
3:10 {9} In this the children of God are manifest, and the
     children of the devil: whosoever doeth not righteousness is
     not of God, {10} neither he that loveth not his brother.

 (9) The conclusion: by a wicked life they are known who are
     governed by the Sprit of the devil: and by a pure life who
     are God's children.
 (10) He begins to commend charity towards the brethren as
      another mark of the sons of God.

1Jo 3:11
3:11 {11} For this is the message that ye heard from the
     beginning, that we should love one another.

 (11) The first reason taken from the authority of God who gives
      the commandment.

1Jo 3:12
3:12 {12} Not as Cain, [who] was of that wicked one, and slew
     his brother.  {13} And wherefore slew he him? Because his
     own works were evil, and his brother's righteous.

 (12) An amplification taken from the contrary example of Cain
      who slew his brother.
 (13) A short digression: Let us not marvel that we are hated by
      the world for doing our duty, for such was the condition
      of Abel who was a just person: and who would not rather be
      like him than Cain?

1Jo 3:14
3:14 {14} We {o} know that we have passed from death unto life,
     because we love the brethren. He that loveth not [his]
     brother abideth in death.

 (14) The second reason: Because charity is a testimony that we
      are translated from death to life: and therefore hatred
      towards the brethren is a testimony of death, and whoever
      nourishes it fosters death in his bosom.
     (o) Love is a token that we are translated from death to
         life, for by the effects the cause is known.

1Jo 3:15
3:15 {15} Whosoever hateth his brother is a murderer: and ye
     know that no murderer hath eternal life abiding in him.

 (15) A confirmation: Whoever is a murderer, is in eternal
      death: he who hates his brother is a murderer, therefore
      he is in death. Thereupon follows the other side: He that
      loves his brother has passed to life, for indeed we are
      born dead.

1Jo 3:16
3:16 {16} Hereby perceive we the love [of God], because he laid
     down his life for us: and we ought to lay down [our] lives
     for the brethren.

 (16) Now he shows how far Christian charity extends, even so
      far, that according to the example of Christ every man
      forgets himself, to provide for and help his brethren.

1Jo 3:17
3:17 {17} But whoso hath this {p} world's good, and seeth his
     brother have need, and {q} shutteth up his bowels [of
     compassion] from him, how dwelleth the love of God in him?

 (17) He reasons by comparisons: for if we are bound even to
      give our life for our neighbours, how much more are we
      bound to help our brothers' needs with our goods and
      substance?
     (p) Wherewith this life is sustained.
     (q) Opens not his heart to him, nor helps him willingly and
         cheerfully.

1Jo 3:18
3:18 {18} My little children, let us not love in word, neither
     in tongue; but in deed and in truth.

 (18) Christian charity stands not in word but in deed, and
      proceeds from a sincere affection.

1Jo 3:19
3:19 {19} And hereby we know that we are of the truth, {20} and
     shall assure our hearts before him.

 (19) He commends charity, by three effects: for first of all,
      by it we know that we are indeed the sons of God, as he
      showed before.
 (20) Therefore it comes that we have a quiet conscience, as on
      the opposite side he that thinks that he has God for a
      judge, because he is guilty to himself either he is never
      or else very rarely quiet, for God has a far sharper sight
      then we, and judges more severely.

1Jo 3:20
3:20 For {4} if our heart condemn us, God is greater than our
     heart, and knoweth all things.

 (r) If an evil conscience convicts us, much more ought the
     judgment of God condemn us, who knows our hearts better
     than we ourselves do.

1Jo 3:21
3:21 {21} Beloved, if our heart condemn us not, [then] have we
     confidence toward God.

 (21) A third effect also rises from the former, that in these
      miseries we are sure to be heard, because we are the sons
      of God: as we understand by the grace of sanctification
      which is only for the elect.

1Jo 3:22
3:22 {22} And whatsoever we ask, we receive of him, because we
     keep his commandments, and do those things that are
     pleasing in his sight.

 (22) The conclusion, that faith in Christ and love one towards
      another are things joined together, and therefore the
      outward testimonies of sanctification must and do answer
      that inward testimony of the Spirit given to us.

1Jo 3:24
3:24 And he that keepeth his commandments dwelleth in him, and
     he in him.  And hereby we know that he abideth in us, by
     the {f} Spirit which he hath given us.

     (f) He means the Spirit of sanctification, whereby we are
         born again and live to God.