¹ tn It is difficult to know whether the phrase καὶ αὕτη ἐστιν (kai Jauth estin) refers (1) to the preceding or (2) to the following material, or (3) to both. The same phrase occurs at the beginning of 1:5, where it serves as a transitional link between the prologue (1:1-4) and the first major section of the letter (1:5-3:10). It is probably best to see the phrase here as transitional as well; thus καί (kai) has been translated “now” rather than “and.” The accusative phrase at the end of v. 25, τὴν ζωὴν τὴν αἰώνιον (thn zwhn thn aiwnion), stands in apposition to the relative pronoun ἥν (Jhn), whose antecedent is ἡ ἐπαγγελία (Jh epangelia; see BDF §295). Thus the “promise” consists of “eternal life.”

² tn The pronoun could refer to God or Jesus Christ, but a reference to Jesus Christ is more likely here.

³ tn Grk “he himself promised.” The repetition of the cognate verb “promised” after the noun “promise” is redundant in English.

⁴ sn The promise consists of eternal life, but it is also related to the concept of “remaining” in 2:24. The person who “remains in the Son and in the Father” thus has this promise of eternal life from Jesus himself. Consistent with this, 1 John 5:12 implies that the believer has this eternal life now, not just in the future, and this in turn agrees with John 5:24.

⁵ sn The noun truth here has been interpreted in various ways: (1) There are a number of interpreters who understand the final noun in this series, truth (ἀληθείᾳ, alhqeia) in an adverbial sense (“truly” or “in sincerity”), describing the way in which believers are to love. If the two pairs of nouns are compared, however, it is hard to see how the second noun with tongue (γλώσσῃ, glwssh) in the first pair can have an adverbial sense. (2) It seems better to understand the first noun in each pair as produced by the second noun: Words are produced by the tongue, and the (righteous) deeds with which believers are to love one another are produced by the truth.

⁶ tn Grk “and.” The Greek conjunction καί (kai) introduces the apodosis of the conditional sentence.

⁷ tn This is a first-class conditional sentence with εἰ (ei) + aorist indicative in the protasis. Reality is assumed for the sake of argument with a first-class condition.

sn The author here assumes the reality of the protasis (the “if” clause), which his recipients, as believers, would also be expected to agree with: Assuming that God has loved us in this way, then it follows that we also ought to love one another. God’s act of love in sending his Son into the world to be the atoning sacrifice for our sins (v. 10) ought to motivate us as believers to love one another in a similar sacrificial fashion. The author made the same point already in 1 John 3:16. But this failure to show love for fellow believers is just what the opponents are doing: In 1 John 3:17 the author charged them with refusing to love their brothers by withholding needed material assistance. By their failure to love the brothers sacrificially according to the example Jesus set for believers, the opponents have demonstrated again the falsity of their claims to love God and know God (see 1 John 2:9).