1 John 3:4 3Everyone who does sin also does lawlessness; and sin is lawlessness.
Following his pattern, John shifts from the positive of new life in Jesus back to discussing the negative of sin. The opposite of having hope, which leads to purity, is sinning, which indicates lawlessness. This verse gives a clear definition of sin (hamartia). The classic definition of sin is a known transgression of God’s law. Sin is purposefully or knowingly ignoring God’s laws, either written in inspired Scripture or written on the conscience through prevenient grace working expressed and experienced in culture and nature (Romans 2:14-15). All sin is lawlessness, and all lawlessness is sin.
The tense of the verb does (poiei) or “practices” is present, implying a lifestyle or something done on a continual basis. Continuous sin will lead to pain and destruction now and for eternity. Sin always has consequences. John does not mean here that we will never sin but that we should not make sin an intentional act that we do. It should be the rarer exception and not a daily occurrence. We must understand the nature of sin in order to see the tremendous transformation offered through God’s grace in Christ.
Life offers us a choice between the light and the darkness. Choosing the way of darkness has serious consequences for our well-being. Since God is light, living in darkness is the rejection of God’s light. God points the way to and through the light by revealing his will to us, particularly in the commands of the Bible. These commands should not be viewed as a burden. The ancient Israelites saw God’s law as a gift to light their path (Psalm 119:11). God’s laws show the way of righteousness (Psalm 1). If Israel obeyed, they would experience many blessings, but disobedience brought curses (Deuteronomy 27-28). The responsibility is clear thus far in the chapter: we must feel sin and pursue righteousness.