In the Old Testament, there is a story about Nebuchadnezzar II, the great king of the Neo-Babylonian empire, that holds the root of Mormonism’s unique interpretation of Christian theology. The king is tormented by a cryptic dream in which he sees an enormous statue of a man, forged from four different metals, destroyed by a stone that was cut from a mountain “without hands.” The stone then becomes a mountain itself that grows to fill the whole earth. Wise men and astrologers throughout the empire try and fail to decode the dream to the intense dismay of the king, who, in a fit of rage, orders the slaughter of all wise men in his kingdom. Concerned, Daniel asks God for a crash course in dream analysis. That night in a vision, God reveals to Daniel the entirety of Nebuchadnezzar’s dream and its accompanying interpretation. Daniel then explains to the king that the statue’s four different metals represent successive kingdoms of men, beginning with Babylon. And the stone represents the indestructible and eternal Kingdom of God.

Most mainstream Christians understand this story in eschatological terms, the Kingdom of God referring to the new world order that will be instituted and presided over by Jesus Christ following his Second Coming. But Mormons have taken the Kingdom of God, in this context, to mean The Church of Jesus Christ of Latter-day Saints—the Mormon Church itself. In Mormon circles, in fact, “stone cut without hands” has become shorthand for the church and the gospel it preaches.

That world-conquering confidence has long been the beating heart of the Mormon Church. To Mormons, the breakneck speed with which the church has grown from just six members at its founding in 1830 to more than 15 million in 2017 represents Daniel’s prophecy fulfilled. But a recent controversy surrounding a New York Times obituary of former church president Thomas S. Monson shows how wobbly that confidence has become, as Mormonism struggles to adapt to a changing world that, in a reversal of Nebuchadnezzar’s dream, threatens to overwhelm it.

Mormonism’s exponential growth has been a comfort and a testament to millions of Mormons for decades. The gospel must be true. How else could this religion have expanded so rapidly? Though I am no longer a practicing member, that’s how I felt growing up in the church. In Sunday school once, an elder stood up in the middle of class, brandishing a magazine rolled up like a stick. He explained, gesturing to the curled pages in his hand, that an article had just been published declaring Mormonism to be the fastest growing religious sect in American history. And if current growth trends continued, he said, there could be 265 million members of the church worldwide by 2080. At the time, the Mormon church was on pace to become the first new major world religion of the twenty-first century.

But the good news that once allayed the fears of the doubters and hardened the resolve of the faithful has evaporated. Mormons don’t source the bulk of their faith to rapid measures of growth, of course; religious conviction can’t be measured like gross domestic product. But the latest numbers make it hard to seriously claim that the Mormon interpretation of Daniel’s prophecy has come to pass, or even that it may yet. In fact, church growth has cooled to its slowest pace since 1937. Mormon supremacy is no longer the foregone conclusion that it was when I was a young believer.