Adapted from the MacArthur Bible Commentary; from 1 John 3.
This passage begins with the phrase “Whoever commits sin” (v. 4). Commits translates from a Greek verb that conveys the idea of habitual practice. Although genuine Christians have a sin nature (1:8) and do behave sinfully, their confession of sin (1:9; 2:1) and acceptance of forgiveness prevent sin from becoming the unbroken pattern of their lives (John 8:31, 34-36; Rom. 6:11; 2 John 9).
An “unbroken pattern of sin” means living in a continuous, habitual lifestyle of sin without genuine repentance or change. It indicates a heart not fully surrendered to God (1 John 3:6). It is those who do not struggle with it— those who deliberately and eagerly revel in their sin, characterized by ongoing disobedience to God, showing no evidence of turning away from sin or being transformed by the Holy Spirit, who need to have their false sense of security shaken.
True believers cannot habitually practice sin.
God builds a certain growing awareness about sin that provides four effective reasons why true Christians cannot habitually practice sin.
Genuine Christians cannot habitually practice sin because sin is incompatible with the law of God, which they love (3:4; Ps. 119:34, 77, 97); Rom. 7:12, 22); whereas habitual sin betrays the ultimate sense of rebellion— living as if there were no laws or ignoring what law exist (James 4:17)— in short, lawlessness.
Genuine Christians cannot habitually practice sin because sin is incompatible with the work of Christ (3:5). Christ died to sanctify (make holy) the believer (2 Cor. 5:21; Eph. 5:25-27). Habitual sin contradicts Christ’s work of breaking the dominion of sin in the believer’s life (Rom. 6:15).
Genuine Christians cannot habitual practice sin because Christ came to destroy the works of the arch-sinner, Satan (3:8). The devil is still operating, but he has been defeated, and in Christ we escape his tyranny. The day will come when all of Satan’s activity will cease in the universe, and he will be sent to hell forever (Rev. 20:10).
Genuine Christians cannot habitually practice sin because sin is incompatible with the ministry of the Holy Spirit, who has imparted a new nature to the believer (3:9; John 3:5-8). This new nature shuns sin, cannot habitually sin, and exhibits the habitual character of righteousness produced by the Holy Spirit. (Gal. 5:22-24).

