After predicting that the Bible would be a forgotten book in a hundred years, Voltaire died in 1778. In 1878, the Bible was still a highly influential book, just as it is today. Voltaire believed the Bible would be a forgotten book because his starting assumptions were wrong. He failed to take into account the fact that the Bible is true. It is the word of God, revealed to man for the purposes of getting to know Him before we meet Him, and he will preserve it.
Voltaire's philosophy was far from unique. Many atheists have predicted the final end of Christianity, and they continue to brag about how either they will win in the future, or even claim they already have. But just as Voltaire was wrong, so also is Bill Nye, who made the same prediction in 2014, wrong. The culture may become more unGodly as their sins become more attractive to them than the Lord who saves us from them, as indeed the Bible predicts, but a total, natural end to Christianity will never be seen.
One of the greatest proofs that God is with His Church comes from the fact that in its beginning, it was persecuted to the max. It was literally born out of persecution as our God came to earth as a man, and rather than listen to Him, the culture put Him on a cross. Many Christians died for professing that they had seen Him alive again, and many others fled for their lives to other places, where they were persecuted again for preaching the same message. The Church grew in such a hostile environment, yet Voltaire assumed it would simply cease to grow when the biggest obstacle was the failed arguments of a philosophy that his contemporary, Isaac Newton, described as being "so senseless and odious to mankind that it never had many professors"(1)?
The modern culture is hard to predict right now. Godlessness reigns, yet it also seems the Church is keeping it at bay. Perhaps we are on the verge of a revival, perhaps we are on the verge of a great apostasy, maybe even on the scale that the Bible does predict will happen in the Last Days. But the world Voltaire envisioned, in which any interest in the Bible would be mere curiosity about the beliefs of our ancestors, will never come to pass. For as long as there are humans, there will be Christians. And they will be persecuted. There will be pockets of safety, and there will be hostile ground. There will be times when truth reigns culturally, and times when it is politically incorrect. There will be times when Satan will cheekily sit on a throne that does not belong to him, and there will be times when God will flick him off that throne like a bug off a leaf. But there will never be a time when the Bible is forgotten.
But something that can be forgotten is your sin. If you're an atheist, like Voltaire, you're probably looking forward to the day when Voltaire's prediction will come true. But as Voltaire was disappointed, so will you be. As I said, Voltaire overlooked the fact that the Bible truly is the word of God. And it contains a gift Voltaire never received: The words of eternal life. It's too late for Voltaire. He stands condemned before God, and awaits his final punishment. But while you live, you can be thankful that the gift Voltaire refused will never perish, because you can now accept it. Come to the Lord Jesus in faith, confess His death and His resurrection, and you will be saved.
References
1. Newton, Isaac, cited in Memoirs of the Life, Writings and Discoveries of Sir Isaac Newton by Sir David Brewster, 1855