I don't remember a time when I believed in Santa Claus. In fact, I remember the very moment I spoiled the illusion for my little brother. "Brent thinks Santa Claus is real," I said at the dinner table. My mom hushed me and pointed at my younger sibling as if we were to keep the secret. They never outright lied; but they also didn’t want to spoil the fun while he was young. 

At some point, even my younger brother fell away from belief in Santa Claus. I'm not sure that fearing a lump of coal at Christmas ever motivated a child to behave, but if it did, you can bet that good behavior evaporated when the belief died. 

What we believe has a powerful effect, not only on our eternity but on how we live now. Take a look at what Jesus said about some who followed Him:

"Yet there are some of you who do not believe." For Jesus had known from the beginning which of them did not believe and who would betray Him. (John 6:64)

It's astounding to imagine that there were some who followed Jesus from early in his ministry, and yet, they did not believe in Him as the Christ. Certainly, there were particular things they believed about Him, but they never came to faith in Him for salvation. The verse associates Judas, the one who would betray Him, with those who don’t believe. This makes it sound like even Judas was an unbeliever from the beginning.

Since a single instant of belief in Jesus is all it takes to receive that free gift, it’s those who never believed in Jesus who are eternally condemned. Now let's take a look at the flip side of this eternal distinction. Just a few verses earlier, Jesus said: 

Most assuredly, I say to you, he who believes in Me has everlasting life.. (John 6:47)

Notice what people get for believing in Jesus. The person who believes in Jesus at any given moment in time receives everlasting life. So, the people who never believed are those who don’t have everlasting life. Those who believe in Jesus are those who have everlasting life right away. I say right away because of the powerful little word, has. Jesus doesn’t say that the believer will have, might have, or possibly could have everlasting life. He says that the person who believes has, which means they possess it right now, currently, the instant they believe. Since everlasting life is an eternal gift, that means it can never be lost or terminated. So, those who never believed are eternally condemned, but those who believe for life have everlasting life right away. 

There's one more point we need to see. Certainly, those who never believed in Jesus did, in fact, believe certain things about Him. After all, they had seen him work miracles and do all kinds of amazing things. What they didn't believe was his offer of everlasting life. Some people believe in Jesus for peace of mind, financial security, or even healing. However, if it's eternal salvation you're after, you must believe in Jesus FOR everlasting life (or some equivalent gift like salvation, Heaven, justification, etc.). Paul said that he was an example for those who would "believe in Him for everlasting life" (1 Timothy 1:16 ESV)

Only those who never believed in the savior will be condemned, and only those who believe in Him for life will be saved. It’s a simple moment of belief in which a person receives the irrevocable gift of everlasting life. 

Now, as we look at the eternal distinction of believer’s obedience, let’s consider what happens if someone doesn’t continue to believe. Jesus gave this amazing parable in which seed fell on different types of soil. In his description of the parable, he said this:

...They believe for a while, but in the time of testing they fall away. (Luke 8:13)

Some say, “If you stop believing, it proves you never really believed.” I’d like to use a deeply theological word: Nonsense. Jesus said that a person can believe for a while and then fall away from that belief. The idea that a person can think they believed only to find out they never did, confuses the meaning of the word. To believe means to be convinced that something is true. 

So, these people believe for a while but then fall away from belief. This is sad because falling away from belief results in a great lack of many of the things that Christ wants to give. In the parable, the one who falls away from belief ends their time bearing no fruit. There is another group who, it seems, continue to believe but their fruit does not completely mature. What Jesus is teaching us is amazingly important today. There are so many people who have believed in Jesus but have later fallen away from that belief. In other words, they've stopped believing what they believed at first. 

The writer of Hebrews helps us understand why this happens when he says:

See to it, brothers and sisters, that none of you has a sinful, unbelieving heart that turns away from the living God. But exhort one another every day… that none of you may be hardened by the deceitfulness of sin. (Hebrews 3:12-13)

The author is writing to Christians who are considering leaving Christianity and going back to Judaism. Notice what causes an unbelieving heart and why they might be considering turning away from the living God. It’s the deceitfulness of sin. For salvation to be given, it only takes a single moment of belief in Jesus; however, the deceitfulness of sin can make whatever fruit we might have grown die on the vine. Sin can even twist our minds to the point we no longer believe.

So, does a person who falls away from belief lose their salvation? Certainly not. Look back at John 6:47. If you've believed in Jesus, you have (presently possess) that gift of eternal life. What's at stake is reward, or in the words of the parable, fruit. For those who let sins grow in their lives, they will miss out on the reward that Christ wants to give. Not all disobedient believers go so far as to fall away from belief. But rest assured, all who fall away from belief are disobedient believers. So, what would an obedient believer do?

But as for you, continue in what you have learned and have firmly believed… (2 Timothy 3:14 ESV)

Here, Paul is talking to one of his young ministry trainees. When he says continue in what you believe, it seems to go beyond simply believing but actually acting on those beliefs. For Timothy and any of us to be obedient believers, we must continue in what we believe. 

Heaven and Hell hinge on belief. For those who never believed Hell awaits, but for those who believe in Jesus for life, Heaven is theirs. Whereas the first eternal distinction is about destination, the second is about experience. If you want to experience reward in Heaven, you must guard yourself against falling away from belief and strive to continue in what you believe. Jesus promises that it will be worth it.