Everyone still sins or you are denying the very reason Jesus died for us. He didn’t save us and we are now perfected. Paul writes in Rom 7:15-20 “For what I am doing, I do not understand. For what I will to do, that I do not practice; but what I hate, that I do. If, then, I do what I will not to do, I agree with the law that it is good. But now, it is no longer I who do it, but sin that dwells in me. For I know that in me (that is, in my flesh) nothing good dwells; for to will is present with me, but how to perform what is good I do not find. For the good that I will to do, I do not do; but the evil I will not to do, that I practice. Now if I do what I will not to do, it is no longer I who do it, but sin that dwells in me.” Twice Paul states sin that dwells in him.

As believers we all still have various degrees of sin because of our weakness of the flesh but God looks at us by the blood of Jesus, the person of Christ who took our place. As the Passover lamb we are passed over in judgment. The blood is applied when it is needed, by our confession of sin and repentance, it continues to cleanse us.

A mature Christian does not claim they are sinless but is one that repents quickly when he does sin.

Ecclesiastes 7:20 “For there is not a just man on earth who does good And does not sin.”

Many of the Scriptures of the believer not sinning are found in the epistle of 1 John. 1 John 3:6-7 “Whoever abides in Him does not sin, Whoever sins has neither seen Him nor known Him.”

Sinneth not ouch (NT:3708) hamartanei (NT:261). Linear present (linear menoon (NT:3164), keeps on abiding) active indicative of hamartanoo (NT:261), "does not keep on sinning." For menoo (NT:3164) (abide) see 1 John 2:6 and John 15:4-10.

John is saying that one does not continue to sin. He who is born again does not CONTINUALLY sin, or is not HABITUALLY a sinner as he was before he came to know Jesus. The born again believer has no compulsion to sin over and over as He once had, being driven by a fallen nature. As free moral agents we have a choice to obey or not; a true believer will wants to be obedient and choose not to sin. The key is “abiding in him,” but none of us abide in him perfectly.

Whosoever sinneth- ho (NT:3543) hamartanoon (NT:261). Present (linear) active articular participle like menoon (NT:3164) above, "the one who keeps on sinning" (lives a life of sin, not mere occasional acts of sin as hamarteesas (NT:261), aorist active participle, would mean).(from Robertson's Word Pictures in the New Testament)

1 John 3:6 Sinneth not. John does NOT teach that believers do not sin, but is speaking of a CHARACTER, a HABIT." Throughout the Epistle he deals with the ideal reality of life in God, in which the love of God and sin exclude each other as light and darkness” (from Vincent's Word Studies of the New Testament)

1 John 3:8: “he that doeth sin is of the devil; for the devil sinneth from the beginning. To this end was the Son of God manifested, that he might destroy the works of the devil.”

The devil “Sinneth” -The present tense indicates continuousness. He sinned in the beginning, and has never ceased to sin from the beginning, and still sinneth.(from Vincent's Word Studies of the New Testament)

1 John 3:8 Sinneth from the beginning ap' (NT:569) archees (NT:740) hamartanei (NT:261). Linear progressive present active indicative, "he has been sinning from the beginning" of his career as the devil. This is his normal life and those who imitate him become his spiritual children” (from Robertson's Word Pictures in the New Testament).

Those who practice God’s ways are His, those who do not practice God’s righteousness are the Devils. The Devil operates with pride and self - seeking and the strength of man without God. Humility defeats the Devil as one puts their trust in Christ they are willing to be conformed to His nature.

He was manifested to take away our sins—This was the complete purpose for Christ’s becoming a man, taking away our sins once for all because “in him is no sin”—present tense, like 3:3, “he is pure,” and 3:7, “he is righteous.”

1 John 3:9. “Whoever has been born of God does not sin, for His seed remains in him; and he cannot sin, because he has been born of God.”

Doeth no sin hamartian (NT:263) ou (NT:3708) poiei (NT:4109). Linear present active indicative as in 1 John 3:4 like hamartanei (NT:261) in 1 John 3:8. The child of God does not have the habit of sin.” (from Robertson's Word Pictures in the New Testament)

1 John 3:9 And he cannot sin kai (NT:2498) ou (NT:3708) dunatai (NT:1394) hamartanein (NT:261). This is a wrong translation, for this English naturally means "and he cannot commit sin" as if it were kai (NT:2498) ou (NT:3708) dunatai (NT:1394) hamartein (NT:261) or hamarteesai (NT:261) (second aorist or first aorist active infinitive). The present active infinitive hamartanein (NT:261) can only mean "and he cannot go on sinning," as is true of hamartanei (NT:261) in 1 John 3:8 and hamartanoon (NT:261) in 1 John 3:6. For the aorist subjunctive to commit a sin see hamarteete (NT:261) and hamartee (NT:261) in 1 John 2:1. A great deal of false theology has grown out of a misunderstanding of the tense of hamartanein (NT:261) here. Paul has precisely John's idea in Romans 6:1 epimenoomen (NT:1936) tee (NT:3543) hamartia (NT:263) (shall we continue in sin, present active linear subjunctive) in contrast with hamarteesoomen (NT:261) in Romans 6:15 (shall we commit a sin, first aorist active subjunctive). from Robertson's Word Pictures in the New Testament)

“whosoever is born of God,” “he cannot sin.” Is not in the definitive sense that he no longer sins. This cannot be what it means because it would contradict what he said in chapter one about our sin and confessing it. If this scripture meant absolute perfect holiness, it would prove not that some Christians MAY be perfect, but all of them are.

We know this to not be so, sin is still active, we are continually fighting against it so it no longer rules over us, but we are to rule over it. But the deposit of the new nature does not have complete control over us. We once lived by our old nature and were unable to choose not to sin, now the normal direction of a Christian’s life is to fight against sin and to live for God. The sinner who does not possess the regeneration of the Spirit will always gravitate toward sin. He cannot choose not to sin but only what kind of sin he will do.

To be “born of God” does not mean there is no sin present but that our new life is incompatible with sin, we are to have a hatred for sin, we see it as an enemy not a friend. We have to see sin as our enemy not just the devil. It may be more of an enemy as we have it with us all the time.

The old sinful nature is not yet completely dead and still causes us to sin. We may occasionally give in to sin, but Sin now becomes the exception and not the rule. If sin is ruling a persons life, that person is probably not redeemed (Rom 6). In fact the way to tell that we are saved is how we feel when we sin, do we have a conviction or is our conscience seared. And if done there is Godly remorse for it. What was once easy to do is hard, we continually fight against it. The Holy Spirit works, through the word of God, to sanctify us or to make us holy this is why it is so important to be continually in the word and not the world. Continual sinning with no change in affection or life shows that a new birth has not occurred.

1 John 5:18-19 “We know that whoever is born of God does not sin ; but he who has been born of God keeps himself, and the wicked one does not touch him.”

1 John 5:18 Lineal present active indicative, "does not keep on sinning," as he has already shown in 1 John 3:4-10. (from Robertson's Word Pictures in the New Testament).

Again the meaning is a changed lifestyle, where sin does not dominate but by faith and self control, obeying the word sin has become the lesser influence on the believer. Sinless perfection is beyond our reach for the time being because the old nature is not eradicated, John (and Paul) writes about practical holiness and obedience that we might not sin. But if any man sins God has given us a provision, the blood of Christ and an advocate – Jesus Christ himself (1 Jn.1).

Matthew Henry writes "All who walk near to God, in holiness and righteousness, are sensible that their best days and duties are mixed with sin. God has given testimony to the sinfulness of the world, by providing a sufficient, effectual Sacrifice for sin, needed in all ages; and the sinfulness of believers themselves is shown, by requiring them continually to confess their sins, and to apply by faith to the blood of that Sacrifice. (from Matthew Henry's Concise Commentary)

1 John 1:8 If we say that we have no sin, we deceive ourselves, and the truth is not in us.

That we have no sin. Hoti (NT:3706) "that," may be taken merely as a mark of quotation: "If we say, sin we have not." On the phrase "to have sin," see the note at John 16:22, and compare "have fellowship," 1 John 1:3. Sin hamartian (NT:263) is not to be understood of original sin, or of sin before conversion, but generally. "It is obvious that this echein (NT:2159) hamartian (NT:263) ("to have sin"), is infinitely diversified, according to the successive measure of the purification and development of the new man. Even the apostle John does not exclude himself from the universal if we say" (Ebrard). (from Vincent's Word Studies of the New Testament)

We deceive ourselves, and lead ourselves and others astray. The same verb as applied to deceivers of various kinds, this would be one of the worst deceptions, to tell people they do not have to be concerned with sin any longer because they cannot sin. A denial of the continual cleansing that is offered to us by the crucifixion of Jesus.