The Geneva Bible Translation Notes, [1599], at sacred-texts.com
(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.
(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 (Co1 13:12)
(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.
(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.
(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.
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.
(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.
(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.
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.
(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.
(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.
(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?
(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.
(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.
(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.
(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.
(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.
(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.
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.
(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.
(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.
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.