So, given that there are many who claim to believe in Christ and yet demonstrate no evidence or fruit that they are saved, just exactly what is the Bible talking about when it talks about believing in Jesus in such a way that it saves?

Perhaps the clue is found in the book of James.  There, in James 2:19, in his discussion of works and faith, the apostle states in reference to someone who claims to have faith, but no works:  “ You believe that God is one. You do well; the demons also believe, and shudder.”

So we should ask this question:  “What’s the difference between the faith of demons and the faith of saved believers?

James would obviously answer that the difference is in the works of demons versus the works of true believers.  Whatever kind of faith demons have in God, it clearly has no effect on how they behave, other than it causes them to shudder when they think of God’s existence, reality and nature—and that because of those things, a terrifying and eternal judgment awaits them.

Exactly what kind of faith is this?  Faith that God will save them?  Obviously not!  Their expectation is judgment.

Among the definitions which the Greek word for faith can signify, there is one which describes the kind of faith characteristic of demons.  They agree with, or give intellectual assent to the fact that God exists.

However, clearly one other definition for faith does not describe them.  They do not trust in, rely on or depend on God for their salvation.

The same could be said for the person who simply believes that Christ is the Son of God and that He exists.  He gives intellectual assent to or agrees with the facts about Jesus Christ.  However, He does not trust in Christ and Christ alone for salvation.

What demonstrates that a person trusts Christ for salvation?  James, again, says that it will be demonstrated by His works.  Clearly, if a person truly is trusting in Christ for salvation, He will seek to please Jesus Christ by how he lives his life.  He appreciates that Christ died for his sins, and because of this attitude of gratitude and His love for Christ, he will show it by some effort given to obeying Jesus Christ.

It follows the universal axiom that what a person believes determines what he does.

Demons do not believe that God or Christ will save them.  They believe God will condemn them.  Therefore, rather than obey Christ, they shudder at the thought of God.

Those who truly believe in a saving way then trust that Christ will save them from their sins and the coming judgment.  They appreciate what Christ has done for them.  Therefore, their trust in Christ for salvation results in some level of obedience to Christ—which is also evidence of their salvation.

As II Corinthians 5:17 puts it, “Therefore if anyone is in Christ, he is a new creature; the old things passed away; behold, new things have come.”

So what is the difference between someone who claims to believe in Christ but is not saved, and another person who claims to believe in Christ and is saved?  The former merely agrees with the facts about Jesus Christ, but does not put His trust in Christ for salvation.  The latter does both.

As a result, his works, or behavior, in one way or another, show his saving faith, as the Apostle James said.

It’s a point of Biblical discernment.