The Geneva Bible Translation Notes, [1599], at sacred-texts.com
(1) He begins with the description of the person of Christ who he makes one and not two: and him both God from everlasting (for he was with the Father from the beginning, and is that eternal life) and also made true man, whom John himself and his companions both heard, beheld, and handled.
(a) I heard him speak, I saw him myself with my eyes, I handled with my hands him that is true God, being made true man, and not I alone, but others also that were with me.
(b) That same everlasting Word by whom all things are made, and in whom only is there life.
(For the life was manifested, and we have seen [it], and bear witness, and (c) shew unto you that eternal life, which was with the Father, and was manifested unto us;)
(c) Being sent by him: and that doctrine is correctly said to be shown, for no man could so much as have thought of it, if it had not been thus shown.
That which we have seen and heard declare we unto you, (2) that ye also may have fellowship with us: and truly our fellowship [is] with the Father, and with his Son Jesus Christ.
(2) The use of this doctrine is this, that all of us being coupled and joined together with Christ by faith, might become the sons of God: in which only consists all true happiness.
(3) This then is the message which we have heard of him, and declare unto you, that God is light, and in him is no darkness at all.
(3) Now he enters into a question, by which we may understand that we are joined together with Christ, that is, if we are governed with his light, which is perceived by the ordering of our life. And thus he reasons, God is in himself most pure light, therefore he agrees well with them who are of the light, but with them that are of the darkness he has no fellowship.
But if we walk in the (d) light, as he is in the light, we have fellowship one with another, (4) and the blood of Jesus Christ his Son cleanseth us from all sin.
(d) God is said to be light by his own nature, and to be in light, that is to say, in that everlasting infinite blessedness: and we are said to walk in light in that the beams of that light shine to us in the Word. (4) A digression the matter at hand, to the remission of sins: for this our sanctification who walk in the light, is a testimony of our joining and knitting together with Christ: but because this our light is very dark, we must obtain another benefit in Christ, that is, that our sins may be forgiven us being sprinkled with his blood: and this in conclusion is the support and anchor of our salvation.
(5) If we say that we have no sin, we (e) deceive ourselves, and the (f) truth is not in us.
(5) There is none but need this benefit, because there is none that is not a sinner.
(e) This fully refutes that perfectness of works of supererogation (doing more than duty requires, the idea that excess good works can form a reserve fund of merit that can be drawn on in favour of sinners) which the papists dream of.
(f) So then, John speaks not thus for modesty's sake, as some say but because it is so indeed.
(6) If we confess our sins, he is (g) faithful and just to (h) forgive us [our] sins, and to cleanse us from all unrighteousness.
(6) Therefore the beginning of salvation is to acknowledge our wickedness and to require pardon from him, who freely forgives all sins, because he has promised to do so and he is faithful and just.
(g) So then our salvation depends on the free promise of God, who because he is faithful and just, will perform that which he hath promised.
(h) Where then are our merits? for this is our true happiness.
(7) If we say that we have not sinned, we make him (i) a liar, and his (k) word is not in us.
(7) A repeat of the former verse, in which he condemned all of sin without exception: so much so that if any man persuade himself otherwise, he does as much as in him lies, make the word of God himself useless and to no effect, yes, he makes God a liar: for to why in times past did we need sacrifices, or now Christ and the gospel, if we are not sinners?
(i) They do not only deceive themselves but are blasphemous against God.
(k) His doctrine shall have no place in us; that is, in our hearts.