2:3 Now 1 by this we know that we have come to know God: 2 if we keep his commandments.
1 tn The translation of καί (kai) at the beginning of 2:3 is important for understanding the argument, because a similar καί occurs at the beginning of 1:5. The use here is not just a simple continuative or connective use, but has more of a resumptive force, pointing back to the previous use in 1:5.
2 tn Grk “know him.” (1) Many take the third person pronoun αὐτον (auton) to refer to Jesus Christ, since he is mentioned in 2:1 and the pronoun αὐτός (autos) at the beginning of 2:2 clearly refers to him. But (2) it is more likely that God is the referent here, since (a) the assurance the author is discussing here is assurance that one has come to know God (all the claims of the opponents in 1:5-2:11 concern knowing and having fellowship with the God who is light); (b) when Jesus Christ is explicitly mentioned as an example to follow in 1 John 2:6, the pronoun ἐκεῖνος (ekeinos) is used to distinguish this from previous references with αὐτός; (c) the καί (kai) which begins 2:3 is parallel to the καί which begins 1:5, suggesting that the author is now returning to the discussion of God who is light, a theme introduced in 1:5. The author will now discuss how a Christian may have assurance that he or she has come to know the God who is light.
3 tn Once more there is the familiar difficulty of determining whether the phrase refers (1) to what precedes or (2) to what follows. Here, because ἐν τούτῳ (en toutw) is followed by a clause introduced by ὅταν (Jotan) which appears to be related, it is best to understand ἐν τούτῳ as referring to what follows. The following ὅταν clause is epexegetical to ἐν τούτῳ, explaining how we know that we love God’s children: “by this we know that we love God’s children, whenever we love God and keep his commandments.”
5 tn The force of the γάρ (gar) at the beginning of 5:3 is similar to another introductory formula used by the author of 1 John, καὶ αὕτη ἐστίν (kai Jauth estin; used in 1:5; 5:4, 11, and 14). The γάρ draws an inference based on the preceding statements, particularly the one in 5:2b, regarding the love of God. If in 5:2 loving God and keeping his commandments is the key to knowing that we love God’s children, it is important to define what the love of God involves, and this is what the author is doing in 5:3. In fact, as the following ἵνα (Jina) clause makes clear, loving God consists in keeping his commandments.
6 tn Once again the genitive could be understood as (1) objective, (2) subjective, or (3) both. Here an objective sense is more likely (believers’ love for God) because in the previous verse it is clear that God is the object of believers’ love.
7 tn Contrary to the punctuation of NA27 and UBS4, it is best to place a full stop (period) following τηρῶμεν (thrwmen) in 5:3. The subordinate clause introduced by ὅτι (Joti) at the beginning of 5:4 is related to the second half of 5:3 which begins with καί (kai). Καί is commonly used by the author to begin a new sentence, probably by analogy with the Hebrew vav consecutive.
7 tn The referent of this pronoun is probably to be understood as God, since God is the nearest previous antecedent.
8 tn Grk “in him.”
9 tn The genitive βίου (biou) is difficult to translate: (1) Many understand it as objective, so that βίος (bios, “material life”) becomes the object of one’s ἀλαζονεία (alazoneia; “pride” or “boastfulness”). Various interpretations along these lines refer to boasting about one’s wealth, showing off one’s possessions, boasting of one’s social status or lifestyle. (2) It is also possible to understand the genitive as subjective, however, in which case the βίος itself produces the ἀλαζονεία. In this case, the material security of one’s life and possessions produces a boastful overconfidence. This understanding better fits the context here: The focus is on people who operate purely on a human level and have no spiritual dimension to their existence. This is the person who loves the world, whose affections are all centered on the world, who has no love for God or spiritual things (“the love of the Father is not in him,” 2:15).