Do I believe that a born again Christian can sin?
This problem confuses many people, particularly those who are young in Christ. I am going to tell you my answer and then give you Scriptures that will support it. Yes, born again Christians can sin in the sense that they don't always do what is right and what pleases God. No, born again Christians can not sin in the sense that they can reject God (or act like Satan which is the thought in 1 John 3). So sin has to be defined by the context. Why do I think Christians can sin or be disobedient to God?
1. David was an old testament saint (a picture of a new testament Christian) and he certainly sinned. 2 Samuel 12, 2 Samuel 24.
2. Most of the new testament letters were written to deal with problems in the assemblies or churches. These problems were either doctrinal (for example, Galatians) or moral (for example 1 Corinthians, particularly chapter 5). Provision is made for excommunication of a "so-called" believer who commits gross moral sin.
3. Our experience agrees with the fact that Christians sin. See Romans 7 and 1 John 1:8-10. Generally we would say that a new life in Christ does not eliminate the "flesh", the sin principle that we receive by our first birth. But the new birth does give us a new attitude toward sin and tools to deal with it. I would say that a Christian is not sinless, but a Christian should sin less (than they did before they received Christ). Scriptures that you might want to look at include:
The next question is, "what happens when a born again believer sins?" Here we must distinguish between salvation and fellowship. My salvation is secure because the blood of the Lord Jesus cleanses from ALL sins, 1 John 1:7 (not just the ones we committed before trusting the Lord). My salvation is dependent on what Christ did for me, not on what I am doing for Christ (and of course what Christ did for me becomes effective when I receive or believe in or trust Him). When Christ died for us all of our sins were future but His death is still sufficient to forgive them all. Now fellowship is broken when I sin, much like fellowship between a husband and wife can be broken by not treating each other right or like fellowship between a father and son if the son disobeys the father. This will make it hard to pray and to be in the presence of the Lord. The solution is to confess that sin as in 1 John 1:9 (that is to say the same thing about our sin that God says) to have fellowship restored. This is like a husband and wife being reconciled after a problem or a father and son being reconciled after the son's disobedience. Notice the relationship is not the issue, the couple is still husband and wife, the father and son are still father and son when the fellowship is broken. But the fellowship is the issue. Notice that 1 John is a family letter dealing with fellowship (1 John 1:3,6, and 7). So we confess our sins, not to be born again and again and again, (since the new birth only happens once) but to restore the sweetness of our fellowship with the Lord and to be in a condition to be used of God.