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 The referent of ἐν τούτῳ (en toutw) here is more difficult to determine than most, because while there are both ἵνα (Jina) and ὅτι (Joti) clauses following, it is not clear whether or not they are related to the ἐν τούτῳ. There are actually three possibilities for the referent of ἐν τούτῳ in 4:17: (1) it may refer to the ἵνα clause which immediately follows, so that the love of believers is brought to perfection in that they have confidence in the day of judgment. The main problem with this interpretation is that since the day of judgment is still future, it necessitates understanding the second use of the preposition “in” (second ἐν [en]) to mean “about” or “concerning” with reference to the day of judgment in order to make logical sense. (2) The ἐν τούτῳ may refer to the ὅτι clause in 4:17b, meaning “love is perfected with us…in that just as he [Christ] is, so also are we in this world.” This makes logical sense, and there are numerous cases where ἐν τούτῳ is explained by a ὅτι clause that follows. However, according to this understanding the intervening ἵνα clause is awkward, and there is no other instance of the phrase ἐν τούτῳ explained by a following ὅτι clause where a ἵνα clause intervenes between the two in this way. (3) Thus, the third possibility is that ἐν τούτῳ refers to what precedes in 4:16b, and this also would make logical sense: “By this – by our residing in love so that we reside in God and he resides in us – is love brought to perfection with us.” This has the additional advantage of agreeing precisely with what the author has already said in 4:12: “If we love one another, God remains in us and his love is brought to perfection in us.” Thus option (3) is best, with the phrase ἐν τούτῳ referring to what precedes in 4:16b, and the ἵνα clause which follows indicates the result of this perfection of love in believers: In the future day of judgment they will have confidence. The ὅτι clause would then give the reason for such confidence in the day of judgment: because just as Jesus is, so also are believers in this world – they are already currently in relationship with God just as Jesus is.
4 tn The preposition μετά (meta) means “with” and modifies the verb τετελείωται (teteleiwtai). If the prepositional phrase modified the noun ἡ ἀγάπη which immediately precedes it, it would almost certainly have the Greek article, thus: ἡ ἀγάπη ἡ μεθ᾿ ἡμῶν (Jh agaph Jh meq’ Jhmwn).
5 tn Grk “that one” (a reference to Jesus is indicated in the context). Once more the author uses the pronoun ἐκεῖνος (ekeinos) to refer to Jesus Christ, as he did in 2:6; 3:3, 5, 7, and 16. A reference to Christ is confirmed in this context because the author says that “just as he is, so also are we [believers] in this world” and since 3:2 indicated that believers are to be like God in the future (but are not yet), the only one believers can be like already in the present age is Jesus Christ.