There are some very peculiar passages within the epistles of the apostle John. Many have questions about who the Antichrist is (1 Jn. 2:18; 4:3) or what a “sin that does not lead to death” (1 Jn. 5:16) is. However, there are a few verses particularly in 1 John that seem to suggest that a Christian is unable to sin. 1 John 3:6 says, “Whoever abides in Him [Christ] does not sin. Whoever sins has neither seen Him nor known Him.” Along with this verse are 3:9 and 5:18 which say pretty much the same thing. However, we know that Paul said in Romans 3:23 that “all have sinned and fall short of the glory of God.” And even in the same epistle, John himself said, “If we say that we have not sinned, we make Him a liar, and His word is not in us” (1:10). So how can he say two things that seem to totally contradict each other? Can a Christian sin?
I hope we can agree that yes, Christians, while special and different from the rest of the world, (1 Pet. 2:9) are able to and do sin. So how can John say that whoever abides in Christ, who is walking “in the light as He is in the light” (1:7) does not sin? The answer lies in the definitions of words. To abide in something is not just to be in something at some point, but rather it is to remain or stay in something. The same could be said for Biblical terms like living (Rom. 8:5) or walking (Eph. 4:1). This abiding demand that one be continuously doing something. And if we are abiding “in Christ,” (Rom. 8:1; Eph. 1:3) as John is pointing out here, we are not living in continuous sin. In other words, while the Christian does sin, the Christian cannot live in sin. If the Christian chooses to live in sin, then they are no longer “in Christ” and they are not “walking in the light as He is in the light.”
God is not going to force anyone into a lifestyle that they, by their actions, choose not to live. Similarly, He is not going to force anyone into heaven against their will. God has given us the incredible gift of free will. But thanks be to Him that the believer can have security in Christ, (Jn. 10:28-29) which is contingent on the state of their soul.