Jamieson, Fausset & Brown

If anyone says, “I love God,” but hates his brother, he is a liar.

“The true ideal of man, lost in Adam, is realized in Christ, in whom God is revealed as He is, and man as he ought to be.”

Everyone who believes that Jesus is the Christ has been born of God, and everyone who loves the Father also loves those born of Him.

“Christ is the "only-begotten Son" by generation; we become begotten sons of God by regeneration and adoption. every one that loveth him that begat--sincerely, not in mere profession (1Jo 4:20). loveth him also that is begotten of him--namely, "his brethren" (1Jo 4:21).”

By this we know that we love the children of God: when we love God and keep His commandments.

“"Love to one's brother is prior, according to the order of nature (see on 1Jo 4:20); love to God is so, according to the order of grace (1Jo 5:2).”

because everyone born of God overcomes the world. And this is the victory that has overcome the world: our faith.

“16:11). this is the victory that overcometh--Greek aorist, ". . . that hath (already) overcome the world": the victory (where faith is) hereby is implied as having been already obtained (1Jo 2:13;”

Who then overcomes the world? Only he who believes that Jesus is the Son of God.

“Who--"Who" else "but he that believeth that Jesus is the Son of God:" "the Christ" (1Jo 5:1)? Confirming, by a triumphant question defying all contradiction, as an undeniable fact, 1Jo 5:4, that the victory which overcomes the world is faith.”

This is the One who came by water and blood, Jesus Christ—not by water alone, but by water and blood.

“John Baptist came only baptizing with water, and therefore was not the Messiah. Jesus came first to undergo Himself the double baptism of water and blood, and then to baptize us with the Spirit-cleansing, of which water is the sacramental seal, and with His atoning…”

For there are three that testify:

“A scholium quoted in Matthæi, shows that the words did not arise from fraud; for in the words, in all Greek manuscripts "there are three that bear record," as the Scholiast notices, the word "three" is masculine, because the three things (the Spirit, the water…”

the Spirit, the water, and the blood—and these three are in agreement.

“By the baptism then received by Christ, and by His redeeming blood-shedding, and by that which the Spirit of God, whose witness is infallible, has effected, and still effects, by Him, the Spirit, the water, and the blood, unite, as the threefold witness, to verify…”

And this is that testimony: God has given us eternal life, and this life is in His Son.

“Not only "promised" it. life is in his Son--essentially (Joh 1:4; 14:6); bodily (Col 2:9); operatively (2Ti 1:10) [LANGE in ALFORD].”

Whoever has the Son has life; whoever does not have the Son of God does not have life.

“In the former clause "has" bears the emphasis; in the second, life. To have the Son is to be able to say as the bride, "I am my Beloved's, and my Beloved is mine" [So 6:3].”

I have written these things to you who believe in the name of the Son of God, so that you may know that you have eternal life.

“These things--This Epistle. He, towards the close of his Gospel (Joh 20:30, 31), wrote similarly, stating his purpose in having written. In 1Jo 1:4 he states the object of his writing this Epistle to be, "that your joy may be full."”

If anyone sees his brother committing a sin not leading to death, he should ask God, who will give life to those who commit this kind of sin.

“If any . . . see--on any particular occasion; Greek aorist. his brother--a fellow Christian. sin a sin--in the act of sinning, and continuing in the sin: present. not unto death--provided that it is not unto death.”

We know that anyone born of God does not keep on sinning; the One who was born of God protects him, and the evil one cannot touch him.

“This 1Jo 5:18 warns against abusing 1Jo 5:16, 17, as warranting carnal security. whosoever--Greek, "every one who." Not only advanced believers, but every one who is born again, "sinneth not."”

And we know that the Son of God has come and has given us understanding, so that we may know Him who is true; and we are in Him who…

“Plainly it is as the Mediator of ETERNAL LIFE to us that Christ is here contemplated. The Greek is, "The true God and eternal life is this" Jesus Christ, that is, In believing in Him we believe in the true God, and have eternal life.”