¹ tn Once again there is the problem (by now familiar to the interpreter of 1 John) of determining whether the phrase ἐν τούτῳ (en toutw) in 3:10 refers (1) to what precedes or (2) to what follows. If it refers to what precedes, it serves to conclude the unit which began with 2:28. The remainder of 3:10 would then form a transition to the following material (another “hinge” passage). On the other hand, if the phrase ἐν τούτῳ refers to what follows, then the entirety of 3:10 is a summary statement at the end of 2:28-3:10 which recapitulates the section’s major theme (conduct is the clue to paternity), and provides at the same time a transition to the theme of loving one’s brother which will dominate the following section (3:11-24). Although R. E. Brown (Epistles of John [AB], 416) prefers to see the phrase as referring to the preceding material, it makes better sense to refer it to the remainder of 3:10 that follows, and see the entirety of 3:10 as both a summary of the theme of the preceding section 2:28-3:10 and a transition to the following section 3:11-24.

² tn See note on the term “fellow Christian” in 2:9.

sn Does not love his fellow Christian. The theme of loving one’s fellow Christian appears in the final clause of 3:10 because it provides the transition to the second major section of 1 John, 3:11-5:12, and specifically to the following section 3:11-24. The theme of love will dominate the second major section of the letter (see 1 John 4:8).

³ sn Since the author states that Cain…was of the evil one (ἐκ τοῦ πονηροῦ, ek tou ponhrou), in the immediate context this imagery serves as an illustration of 3:8a: The person who practices sin is of the devil (ἐκ τοῦ διαβόλου, ek tou diabolou). This is similar to John 8:44, where Jesus told his opponents “you people are from your father the devil…[who] was a murderer from the beginning.” In both Jewish and early Christian writings Cain is a model for those who deliberately disbelieve; Testament of Benjamin 7:5 looks forward to the punishment of those who “are like Cain in the envy and hatred of brothers.” It is not difficult to see why the author of 1 John used Cain here as a model for the opponents in light of their failure to “love the brothers” (see 1 John 3:17).

⁴ tn For the Greek verb σφάζω (sfazw) L&N 20.72 states, “to slaughter, either animals or persons; in contexts referring to persons, the implication is of violence and mercilessness – ‘to slaughter, to kill.’” As a reflection of this nuance, the translation “brutally murdered” has been used.