Behold, what manner of love the Father hath bestowed upon us, that we should be called the sons of God: therefore the world knoweth us not, because it knew him not.
That we should be called — That is, should be, the children of God. Therefore the world knoweth us not - They know not what to make of us. We are a mystery to them.
 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 like him; for we shall see him as he is.
It doth not yet appear — Even to ourselves.
What we shall be — It is something ineffable, which will raise the children of God to be, in a manner, as God himself. But we know, in general, that when he, the Son of God, shall appear, we shall be like him - The glory of God penetrating our inmost substance.
For we shall see him as he is — Manifestly, without a veil. And that sight will transform us into the same likeness.
 And every man that hath this hope in him purifieth himself, even as he is pure.
And every one that hath this hope in him — In God.
 Whosoever committeth sin transgresseth also the law: for sin is the transgression of the law.
Whosoever committeth sin — Thereby transgresseth the holy, just, and good law of God, and so sets his authority at nought; for this is implied in the very nature of sin.
 And ye know that he was manifested to take away our sins; and in him is no sin.
And ye know that he — Christ.
Was manifested — That he came into the world for this very purpose.
To take away our sins — To destroy them all, root and branch, and leave none remaining.
And in him is no sin — So that he could not suffer on his own account, but to make us as himself.
 Whosoever abideth in him sinneth not: whosoever sinneth hath not seen him, neither known him.
Whosoever abideth in communion with him, by loving faith, sinneth not - While he so abideth. Whosoever sinneth certainly seeth him not - The loving eye of his soul is not then fixed upon God; neither doth he then experimentally know him - Whatever he did in time past.
 Little children, let no man deceive you: he that doeth righteousness is righteous, even as he is righteous.
Let no one deceive you — Let none persuade you that any man is righteous but he that uniformly practises righteousness; he alone is righteous, after the example of his Lord.
 He that committeth sin is of the devil; for the devil sinneth from the beginning. For this purpose the Son of God was manifested, that he might destroy the works of the devil.
He that committeth sin is a child of the devil; for the devil sinneth from the beginning - That is, was the first sinner in the universe, and has continued to sin ever since.
The Son of God was manifested to destroy the works of the devil — All sin. And will he not perform this in all that trust in him?
 Whosoever is born of God doth not commit sin; for his seed remaineth in him: and he cannot sin, because he is born of God.
Whosoever is born of God — By living faith, whereby God is continually breathing spiritual life into his soul, and his soul is continually breathing out love and prayer to God, doth not commit sin. For the divine seed of loving faith abideth in him; and, so long as it doth, he cannot sin, because he is born of God - Is inwardly and universally changed.
 In this the children of God are manifest, and the children of the devil: whosoever doeth not righteousness is not of God, neither he that loveth not his brother.
Neither he that loveth not his brother — Here is the transition from the general proposition to one particular.
 Not as Cain, who was of that wicked one, and slew his brother. And wherefore slew he him? Because his own works were evil, and his brother's righteous.
Who was of the wicked one — Who showed he was a child of the devil by killing his brother.
And wherefore slew he him — For any fault? No, but just the reverse; for his goodness.
 Marvel not, my brethren, if the world hate you.
Marvel not if the world hate you — For the same cause.
 We know that we have passed from death unto life, because we love the brethren. He that loveth not his brother abideth in death.
We know — As if he had said, We ourselves could not love our brethren, unless we were passed from spiritual death to life, that is, born of God.
He that loveth not his brother abideth in death — That is, is not born of God. And he that is not born of God, cannot love his brother.
 Whosoever hateth his brother is a murderer: and ye know that no murderer hath eternal life abiding in him.
He, I say, abideth in spiritual death, is void of the life of God. For whosoever hateth his brother, and there is no medium between loving and hating him, is, in God's account, a murderer: every degree of hatred being a degree of the same temper which moved Cain to murder his brother.
And no murderer hath eternal life abiding in him — But every loving believer hath. For love is the beginning of eternal life. It is the same, in substance, with glory.
 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.
The word God is not in the original. It was omitted by the apostle just as the particular name is omitted by Mary, when she says to the gardener, "Sir, if thou hast borne him hence;" and by the church, when she says, "Let him kiss me with the kisses of his mouth," Song of Solomon 1:2; in both which places there is a language, a very emphatical language, even in silence. It declares how totally the thoughts were possessed by the blessed and glorious subject. It expresses also the superlative dignity and amiableness of the person meant, as though He, and He alone, was, or deserved to be, both known and admired by all.
Because he laid down his life — Not merely for sinners, but for us in particular. From this truth believed, from this blessing enjoyed, the love of our brethren takes its rise, which may very justly be admitted as an evidence that our faith is no delusion.
 But whoso hath this world's good, and seeth his brother have need, and shutteth up his bowels of compassion from him, how dwelleth the love of God in him?
But whoso hath this world's good — Worldly substance, far less valuable than life.
And seeth his brother have need — The very sight of want knocks at the door of the spectator's heart.
And shutteth up — Whether asked or not.
His bowels of compassion from him, how dwelleth the love of God in him — Certainly not at all, however he may talk, 1 John 3:18, of loving God.
 My little children, let us not love in word, neither in tongue; but in deed and in truth.
Not in word — Only.
But in deed — In action: not in tongue by empty professions, but in truth.
 And hereby we know that we are of the truth, and shall assure our hearts before him.
And hereby we know — We have a farther proof by this real, operative love.
That we are of the truth — That we have true faith, that we are true children of God.
And shall assure our hearts before him — Shall enjoy the assurance of his favour, and the "testimony of a good conscience toward God." The heart, in St. John's language, is the conscience. The word conscience is not found in his writings.
 For if our heart condemn us, God is greater than our heart, and knoweth all things.
For if we have not this testimony, if in anything our heart, our own conscience, condemn us, much more does God, who is greater than our heart - An infinitely holier and a more impartial Judge.
And knoweth all things — So that there is no hope of hiding it from him.
 Beloved, if our heart condemn us not, then have we confidence toward God.
If our heart condemn us not — If our conscience, duly enlightened by the word and Spirit of God, and comparing all our thoughts, words, and works with that word, pronounce that they agree therewith.
Then have we confidence toward God — Not only our consciousness of his favour continues and increases, but we have a full persuasion, that whatsoever we ask we shall receive of him.
 And this is his commandment, That we should believe on the name of his Son Jesus Christ, and love one another, as he gave us commandment.
And this is his commandment — All his commandments in one word.
That we should believe and love — in the manner and degree which he hath taught. This is the greatest and most important command that ever issued from the throne of glory. If this be neglected, no other can be kept: if this be observed, all others are easy.
 And he that keepeth his commandments dwelleth in him, and he in him. And hereby we know that he abideth in us, by the Spirit which he hath given us.
And he that keepeth his commandments — That thus believes and loves.
Abideth in him, and God in him: and hereby we know that he abideth in us, by the Spirit which he hath given us — Which witnesses with our spirits that we are his children, and brings forth his fruits of peace, love, holiness. This is the transition to the treating of the Holy Spirit which immediately follows.