Coming to saving grace in Jesus Christ means that the power of sin over us has been broken. We received forgivness for our sins, but we are still sinful. How can I explain it? Sin is in-born in us. We inherited it from Adam. It will with us until the day we die. Humans have a sinful nature. Yes, while we as Christians are not supposed to sin, I don't know anyone (period) on the face of the earth who does not sin. I only know of one person who ever lived that did not sin and that was my Lord and Savior Jesus Christ. Even Paul, the world's second best evangelist and missionary had trouble with this. And I don't know anyone who would doubt that Paul wasn't saved. Paul said:
"For that which I do I allow not: for what I would, that do I not; but what I hate, that do I. If then I do that which I would not, I consent unto the law that it is good. Now then it is no more I that do it, but sin that dwelleth in me. For I know that in me (that is, in my flesh,) dwelleth no good thing: for to will is present with me; but how to perform that which is good I find not. For the good that I would I do not: but the evil which I would not, that I do. Now if I do that I would not, it is no more I that do it, but sin that dwelleth in me. I find then a law, that, when I would do good, evil is present with me. For I delight in the law of God after the inward man: But I see another law in my members, warring against the law of my mind, and bringing me into captivity to the law of sin which is in my members. O wretched man that I am! who shall deliver me from the body of this death? I thank God through Jesus Christ our Lord. So then with the mind I myself serve the law of God; but with the flesh the law of sin." Romans 7:15-25
Even Paul had trouble in this area.