If we say that we have no sin, we deceive ourselves, and the truth is not in us. 1 John 1:8.
All of us who are born into this world are born separated from God. Jesus provided a way by which we can be brought back into the relationship with God that was severed when Adam sinned.
The first symptom of being born separated from God is that we are born self-centered. That's the problem. We are all self-centered. From this self-centeredness springs everything that we call sin. And apart from God this condition will continue. Perhaps it would be well to remind ourselves of this premise: "None of the apostles and prophets ever claimed to be without sin. Men who have lived the nearest to God, men who would sacrifice life itself rather than knowingly commit a wrong act, men whom God has honored with divine light and power, have confessed to the sinfulness of their nature."--The Acts of the Apostles, p. 561. We are sinners by nature, and will remain so until Jesus comes again.
Please notice that we are sinners by birth, and that we will continue to be sinners by nature, until Jesus comes again, whether we're sinning or not. When the apostles and prophets admitted and confessed the sinfulness of their nature, they weren't saying that they were continuing to sin. When Paul said that he was the chief of sinners, he didn't mean that he was sinning all the time. Even before Paul was converted on the Damascus road, his behavior was above reproach. He was one of the best livers around. His conversion didn't result in a sudden moral decline. But he drew closer to Jesus, he realized more and more the sinfulness of his nature. "The closer you come to Jesus, the more faulty you will appear in your own eyes; for your wisdom will be clearer, and your imperfections will be seen in broad and distinct contrast to His perfect nature. This is evidence that Satan's delusions have lost their power."--Steps to Christ, pp. 64, 65.
It is only through union with Christ, through relationship with Him, and dependence upon Him moment by moment, that we are enabled to be truly obedient, in spite of the sinfulness of our natures.