If so, then is it fair to say that if you believe in eternal life, you will live forever?
If we say yes, we are saying that eternal life is a result of the power of belief.
Yes, the irony is obvious. But why is there an irony? The apparent irony arises when God becomes a matter of belief.
When we relegate God into a matter of belief, everybody is none the better... Regardless of whether or not he subscribes to that belief. God is just a matter of philosophy. If we reduce God into a mere concept, we are the very cause of the people's unbelief of a true and living God.
The way we respond when we are challenged will reveal how we really see God.
If we see God as a concept, we will retreat into a non-trespass zone. “This is my belief, that is your belief, so let’s leave it as that.” There is no motivation. Fairly stated, nobody has the right to go any further than that. Because we can agree to disagree about concepts. When our gospel is rejected, we feel personally offended. Our philosophy, which reflects our own depth of character, is being ridiculed.
If we see God as a Person, we do not retreat into a non-trespass zone. “I hope you’ll get to know God. Because He already knows you.” There is motivation. Correctly stated, everyone has the right to interfere and challenge God's credibility, or defend it. Because we cannot agree to disagree about the existence of a Person. When our gospel is rejected, we do not take offense. God is being rejected, not our personal philosophy.
Coming back to our question. If you believe in eternal life, will you live forever?
Don't fool yourself. You don’t live a minute longer by sheer belief. You’re missing the point.
God is not a matter of belief. He appeared in human history. We are saved because He saved us. Not because of the power of our belief.