[3:8] 1 sn The person who practices sin is of the devil. 1 John 3:10 and John 8:44 might be cited as parallels, because these speak of opponents as the devil’s “children.” However, it is significant that the author of 1 John never speaks of the opponents as “fathered by the devil” in the same sense as Christians are “fathered by God” (3:9). A concept of evildoers as “fathered” by the devil in the same sense as Christians are fathered by God would imply a much more fully developed Gnosticism with its dualistic approach to humanity. The author of 1 John carefully avoids saying that the opponents are “fathered by the devil,” because in Johannine theology not to be fathered by God is to be fathered only by the flesh (John 1:13). This is a significant piece of evidence that 1 John predates the more fully developed Gnosticism of the 2nd century. What the author does say is that the opponents (“the one who practices sin”) are from the devil, in the sense that they belong to him and have given him their allegiance.
[3:8] 3 tn Here εἰς τοῦτο (eis touto) states the purpose for the revelation of God’s Son. However, the phrase offers the same difficulty as all the ἐν τούτῳ (en toutw) phrases in 1 John: Does it refer to what precedes or to what follows? By analogy with the ἐν τούτῳ construction it is probable that the phrase εἰς τοῦτο here refers to what follows: There is a ἵνα (Jina) clause following which appears to be related to the εἰς τοῦτο, and in fact is resumptive (that is, it restates the idea of “purpose” already expressed by the εἰς τοῦτο). Thus the meaning is: “For this purpose the Son of God was revealed: to destroy the works of the devil.”
[3:8] 4 tn In the Gospel of John λύσῃ (lush) is used both literally and figuratively. In John 1:27 it refers to a literal loosing of one’s sandal-thong, and in John 2:19 to a destruction of Jesus’ physical body which was understood by the hearers to refer to physical destruction of the Jerusalem temple. In John 5:18 it refers to the breaking of the Sabbath, in John 7:23 to the breaking of the law of Moses, and in John 10:35 to the breaking of the scriptures. The verb is again used literally in John 11:44 at the resurrection of Lazarus when Jesus commands that he be released from the graveclothes with which he was bound. Here in 1 John 3:8 the verb means, with reference to “the works of the devil,” to “destroy, bring to an end, abolish.” See BDAG 607 s.v. λύω 4 and F. Büchsel, TDNT 4:336.