1 John 3: 9 – 10
As was pointed out in connection with verse 6, adding such phrases as “continue to” and “go on” to John’s statements about sinning is not justified on the basis of the Greek text. As before, the statements are absolute. One who is born of God (cf. 2:29; 4:7; 5:1, 4, 18) does not sin precisely because God’s seed remains in him, and he cannot sin because he has been born of God. “God’s seed” is His nature, given to each believer at salvation (John 1:13; 2 Peter 1:4). The point here is that the child partakes of the nature of his Parent. The thought of a sinless Parent who begets a child who only sins a little is far from the author’s mind. As always, John dealt in stark contrasts. All sin is devilish (1 John 3:8); it does not stem from the believer’s regenerate nature, God’s seed, but the child of God cannot and does not sin. The explanation here is the same as that given in verse 6. The “new man” (or “new self”; Eph. 4:24; Col. 3:10) is an absolutely perfect new creation. By insisting on this point, John was seeking to refute a false conception about sin. Sin is not, nor ever can be, anything but satanic. It can never spring from what a Christian truly is at the level of his regenerate being.
Literally, the first phrase of this verse is (v.10a), “By this are manifest the children of God and the children of the devil.” The words “by this” probably refer back to the whole previous discussion. By sharply differentiating between sin and righteousness, John made plain the fundamental way in which God’s children are manifest over against the children of the devil. The key to his idea is the word “manifest” in which the ideas presented in 2:29 and 3:1 are touched again. Because a child of God is sinless at the core of his being, he can never be “manifest” through sin as can a child of the devil. While an unsaved person can display his true nature through sin, a child of God cannot. When a Christian sins, he conceals who he really is rather than making it manifest. If the readers perceive someone doing real righteousness, then—but only then—can they perceive this action as a true product of new birth (2:29) and can thus behold God’s love (3:1). This consideration is crucial to John’s advancing argument.
Walvoord, J. F., & Zuck, R. B., Dallas Theological Seminary. (1985). The Bible Knowledge Commentary: An Exposition of the Scriptures (Vol. 2, p. 895). Wheaton, IL: Victor Books.