Disclaimer: I could say plenty about this topic, but to save time, I’m only mentioning a few basics.
Do you find yourself (or someone you know) asking if one is really a Christian if they still feel the urge to do sinful things? What about when one does sinful things? If a Christian has the Holy Spirit inside of them then they should only want to do (and then only do) what the Spirit wants, right?
The thing is, even though we may have the Holy Spirit living in us, we’re still human and, consequentially, sinners. The human nature is to sin while the Spirit’s nature is to do the will of God. Just because you invite Jesus to live inside of you doesn’t mean that all of your sinful urges are *poof!* magically gone.
Christians are humans, just like everyone else. What makes us different is that we realize that we are sinners, we realize that we need a savior to save us from our sins, and we accept Jesus Christ as our Savior. In return, we attempt to mimic Jesus in the way we live our lives; that’s why we are called “Christians,” or little Christs.
Even Paul, who wrote a lot of the New Testament, had the battle of God’s will versus sinful nature inside of him.
“I do not understand what I do. For what I want to do I do not do, but what I hate I do. And if I do what I do not want to do, I agree that the law is good. As it is, it is no longer I myself who do it, but it is sin living in me. For I know that good itself does not dwell in me, that is, in my sinful nature. For I have the desire to do what is good, but I cannot carry it out. For I do not do the good I want to do, but the evil I do not want to do—this I keep on doing. Now if I do what I do not want to do, it is no longer I who do it, but it is sin living in me that does it. So I find this law at work: Although I want to do good, evil is right there with me. For in my inner being I delight in God’s law; but I see another law at work in me, waging war against the law of my mind and making me a prisoner of the law of sin at work within me. What a wretched man I am! Who will rescue me from this body that is subject to death?” Romans 7:15-24
Jesus is the only man who does not have sinful nature. As Christians we might have Him living inside of us but that doesn’t mean we don’t have sinful nature. So the next time you start to wonder “Am I really a Christian?” because you [have the desire to] sin, ask yourself instead if you believe Jesus is the Son of God who came to die on the cross for your sins and if you are attempting to live your life as He did. If the answer is yes, then, chances are, you are, indeed, a Christian. Don’t worry: we’re all human here.