There are different beliefs between some Christian denominations about salvation. A few are of the opinion that once you have accepted Christ as Savior, you can't be lost, and that if you commit sin, you must have never been saved in the first place. Many Baptists will say this is a doctrine of eternal security.

I won't quibble with a statement that nothing can force you to stop being a Christian. But I absolutely believe that you can walk away on your own accord.

Dake has supplied a long list of scriptures dealing with sin, salvation, grace, and whether or not you can be lost. The full list is listed below, along with scripture links. They are broken down by author. Keep in mind that in the Old Testament, they were largely written to God's people, the Jews. In the New Testament, they were largely written to Christian groups, particularly the churches that Paul founded.

This summary will provide clear answers that at least according to the Bible, which should be an ultimate authority, people who are declared as being members of the Christian body have in fact fallen away, and this is warned against repeatedly to Christians, making clear that it was a real possibility. So if you're coming from a background where you might have questions about God's stance on these issues, read the following scriptures and pray about what God is telling you about them.

Even if you are sure of what you believe, I find these scriptures are a real good summary of what God expects of His followers.