This is a question that I've been wrestling though on a personal level for years. I grew up in the church and have known many people (friends and acquaintances) that have claimed to be Christians, but yet their lives don't back it up. For years I have pondered the question, "Is it possible to truly know Christ, and not change?" The decision I came to quite a few years ago, is the same one that I claim today. WITHOUT REPENTANCE, you CANNOT be saved. I know that sounds really harsh but let me explain what I mean.
A common misconception that most people have about Christianity is that, if you attend church you're a Christian; if you read your Bible, you're a Christian; if you speak the Christian lingo, you're a Christian....you get the point. This is a completely incomplete (if that makes sense) way to look at it. Are we defined by what we do? Do our works make us Christian. Absolutely not (Eph. 2:8-9)! Don't hear me say in this post that works make us Christian because that is absolutely wrong. It is only by God's Grace that we are saved.
But let's examine something, In 2 Corinthians, 5:14-21 (great verses....definitely a must read) Paul talks about how, when we come to know Christ as our savior, we are to be controlled by his love (v.14). When we become a Christian, we are a new creation. That is what it means to be born again, we change in mind, heart, and disposition. We are DIFFERENT. Friend, if you have not seen a change in your actions, or desires at all, there honestly may be a problem. I don't want to sound preachy at all. If you knew my heart, you would understand that I struggle as well with sin. We all do. The difference when we are saved is that we are no longer SLAVES (Romans 6). We are no longer slaves to sin. We can have victory over it because Christ is in us! So repentance has to happen because we become new. We have the mind of Christ. Our desires change, we are a new creation!!! Isn't that good news? True salvation must be accompanied with true repentance. The problem with many in the church today is that they are going through the motions. They don't own their faith, they just put on a front. But we are commanded to flee the things of our old self, and set our mind on things above (Col. 3:1-5). We are called to a higher standard. It is a life that depends on God.
The truth is, the Christian life is IMPOSSIBLE to lead without God's help. Apart from him we are sinners, and without his strength we can do nothing. Do yourself a favor and thank God for saving you (if you have come to faith), and choose today to live on his strength alone. Be encouraged, walk in the light (1 John)!