What Does I John 3:9 Mean When It Says A Christian 'Cannot Sin'?

I John 3:9 reads “Whosoever is born of God doth not commit sin; for his seed remaineth in him: and he cannot sin, because he is born of God.” Some take this verse to mean that a Christian never sins, but that position clearly contradicts I John 1:8,10 which teaches everybody sins, at least every now and then.Some try to resolve the difficulty by saying I John 3:9 is talking about the “practice” of sin, but that doesn’t help either since it is not impossible for a Christian to practice sin (e.g., I Cor 5:1). I think we’ve all seen Christians who have fallen away into the practice of sin.I guess it is true the Greek present tense sometimes means "continuous action," but many times it just means "action not yet completed" (Vines). "The present tense is the linear tense; it describes an act as in progress" (Vaughan and Gideon, A Greek Grammar of the New Testament). Of course that is what's meant by the grammar category “present tense” - something happening in the present.Examples of this very common use are Matt 8:25, when the disciples in the ship asked Jesus to save them from the waves, “we perish.” The word “perish” is present tense, but not repetitious. The word “buyeth” in Matt 13:44 is present tense, but is referring to a one time purchase, not continuous action. The word “maketh” in Acts 9:34 is present tense and refers to a one time act of physical healing.The key to reconciling I John 3:9 with I John 1:8,10 is not to understand the word “sin” in I John 3:9 as “practice sin” (because as I said, it is not impossible for a Christian to practice sin), but to understand the word “cannot” as “should not” (inconsistency). Let me illustrate: Suppose I tell my daughter Leah to drive down to the store and get a loaf of bread and bring it right back for supper. Suppose a friend Leah sees at the store says she is on her way to a ballgame and asks Leah to go with her. Leah should answer “I cannot go,” but this wouldn’t mean it is impossible for Leah to go with her friend to the ballgame. Instead, it would simply mean Leah couldn’t do such and remain in obedience to her Dad, and so she is refusing. The Christian “cannot” sin (I John 3:9), but this doesn’t mean it is impossible to sin. Instead it means a Christian cannot sin (one time or many times) and remain in obedience to their heavenly Father, and so we refuse.This use of the word “cannot” is common in the scriptures. Jesus said in Mark 2:19 that the “children of the bridechamber … cannot fast … as long as they have the bridegroom with them.” Does “cannot” in that verse mean it was impossible for the groomsmen to fast, or that it was not appropriate at the time? In Luke 14:20 one replied to the great supper invitation “I have married a wife, and therefore I cannot come.” He didn’t mean it was impossible to come, but his excuse was that because of his marriage, he would not come. I Cor 10:21 teaches Christians “cannot drink the cup of the Lord, and the cup of devils.” That doesn’t mean such is a physical impossibility, but that it is inconsistent for a Christian to claim to serve the Lord (and partake of His supper) and at the same time worship idols - even just one time.The following passages prove we are acting in a way inconsistent with being a Christian when we commit sin, even just one sin:James 2:10 For whosoever shall keep the whole law, and yet offend in one point, he is guilty of allI John 1:7,5 if we walk in the light, as he is in the light … God is light, and in him is no darkness at allI John 2:10 He that loveth his brother abideth in the light, and there is none occasion of stumbling in himI John 2:11 But he that hateth his brother (even one time) is in darkness, and walketh in darknessEph 5:3,8 Christians who "walk as children of light," do not let sin "be once named among them"some others: Ezek 33:12, Mark 8:32-33, Gal 2:11,14,17-18, Acts 8:18-23, I Chron 13:7-10Conclusion: Understand that I John 3:9 is not talking about impossibility, but inconsistency. And we realize it is inconsistent for a Christian to sin whether we are talking about practicing sin or just one sin. Simply put - I John 3:9 means a Christian does not retain his character as a follower of Christ at the moment he sins.