1 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.
2 tn Once again there is the problem of deciding whether the phrase ἐν τούτῳ (en toutw) refers (1) to what precedes or (2) to what follows. When an explanatory or epexegetical ὅτι (Joti) clause follows, and the ὅτι clause is not grammatically unrelated to the phrase ἐν τούτῳ, then the ἐν τούτῳ is best understood as referring to what follows. Here in 3:19-20 there are no less than three ὅτι clauses that follow, one in 3:19 and two in 3:20, and thus there is the difficulty of trying to determine whether any one of them is related to the ἐν τούτῳ phrase in 3:19. It is relatively easy to eliminate the first ὅτι clause (in 3:19) from consideration, because it is related not to ἐν τούτῳ but to the verb γνωσόμεθα (gnwsomeqa) as an indirect discourse clause giving the content of what believers know (“that we are of the truth”). As far as the two ὅτι clauses in 3:20 are concerned, it is difficult to see how believers could know that they belong to the truth (19a) by means of either, since the first speaks of a situation where they are under self-condemnation (“if our heart condemns us…”) and the second ὅτι clause seems to give a further explanation related to the first (“that God is greater than our heart…”). Therefore it seems better to understand the phrase ἐν τούτῳ in 3:19 as referring to the preceding context, and this makes perfectly good sense, because 3:18 concludes with a reference to the righteous deeds with which believers are to love one another, which are produced by the truth.
sn By this refers to the righteous deeds mentioned at the end of 3:18, the expressions of love. It is by doing these deeds that believers assure themselves that they belong to the truth, because the outward action reflects the inward reality of their relationship with God. Put another way, ‘conduct is the clue to paternity.’
3 tn The verb πείθω (peiqw) in the active voice (with the exception of the second perfect and pluperfect) means (a) “to convince”; (b) “to persuade, appeal to”; (c) “to win over, strive to please”; or (d) “to conciliate, pacify, set at ease or rest” (see BDAG 791 s.v. πείθω). Interpreters are generally divided between meaning (a) and meaning (d) for the verb in the present context, with BDAG opting for the latter (although it is pointed out that “the text is not in good order”). In any case the object of the verb πείθω in this context is καρδία (kardia), and this leads to further problems because the meaning of καρδία will affect one’s understanding of πείσομεν (peisomen) here.
4 tn Further difficulties are created by the meaning of καρδία (kardia) in 3:19. Although it may be agreed that the term generally refers to the “center and source of the whole inner life, w. its thinking, feeling, and volition” (BDAG 508 s.v. l.b), this may be further subdivided into references to (a) “the faculty of thought…as the organ of natural and spiritual enlightenment,” that is, the mind; (b) “the will and its decisions”; (c) “the emotions, wishes, desires,” i.e., the emotions or feelings; or (d) “moral decisions, the moral life,” that is, the part of the individual where moral decisions are made, which is commonly called the conscience. Thus καρδία in 3:19 could refer to either the mind, the will, the emotions, or the conscience, and it is not transparently clear which concept the author has primarily in view. In light of the overall context, which seems to discuss the believer’s assurance of his or her standing before God (ἔμπροσθεν αὐτοῦ [emprosqen autou] in 3:19 and the mention of παρρησία [parrhsia, “boldness” or “confidence”] in 3:21) it seems probable that the conscience, that aspect of one’s καρδία which involves moral choices and the guilt or approval for having made them, is primarily in view here. Thus the meaning “convince” is preferred for the verb πείθω (peiqw), since the overall subject seems to be the believer’s assurance of his or her standing before God, especially in the case when (v. 20) the believer’s conscience attempts to condemn him on account of sin.
5 tn Both ἔμπροσθεν (emprosqen) in 3:19 and ἐνώπιον (enwpion) in 3:22 are improper prepositions and both express the meaning “before” in the sense of “in the presence of.” (1) Some interpreters have tried to see a subtle distinction in meaning between the two in 3:19 and 22, but (2) as BDF §214.6 points out, ἔμπροσθεν and ἐνώπιον, along with a third classical expression ἐναντίον (enantion), all refer to being in someone’s presence and are essentially interchangeable. There can be little doubt that once more the author’s fondness for stylistic variation in terminology is at work here.