One of the most striking promises in Scripture is found in 1 Corinthians 15:51–52:

“Behold! I tell you a mystery. We shall not all sleep, but we shall all be changed, in a moment, in the twinkling of an eye, at the last trumpet.”

When Christ returns, those who have died in Him will be raised, and those who are still alive will be instantly transformed. Paul does not describe this transformation as a long, drawn-out process of spiritual growth or purging. Instead, it is sudden, final, and perfect—a sovereign act of God’s power, not the result of our slow climb toward holiness.

This verse contradicts both the Catholic notion of purgatory and the LDS conception of ongoing progression in the spirit world.

Purgatory and Instant Glorification

The Catholic doctrine of purgatory envisions a post-mortem purification for believers who die imperfectly sanctified. As the Catholic Cathecism puts it:

“All who die in God’s grace and friendship, but still imperfectly purified, are indeed assured of their eternal salvation; but after death they undergo purification, so as to achieve the holiness necessary to enter the joy of heaven.”

But this raises a question: if those alive at Christ’s return are instantly perfected without any purgatory, why can’t God do the same for all believers when they die?

If the resurrection involves an immediate, complete glorification, then why do other believers need a separate painful process of purification. Why would God need millennia to do what Scripture says He can—and will—do in a moment?

The LDS Spirit World and Ongoing Progression

Latter-day Saint theology similarly envisions a post-mortal process of learning, repenting, and growing in the “spirit world.” Even faithful members expect to continue climbing the “ladder” of progression after death, with exaltation lying far beyond this life.

As Joseph Smith explained, “When you climb up a ladder, you must begin at the bottom, and ascend step by step, until you arrive at the top; and so it is with the principles of the gospel—you must begin with the first, and go on until you learn all the principles of exaltation. But it will be a great while after you have passed through the veil before you will have learned them.”

But 1 Corinthians 15 and other passages challenge this framework. If God’s people are glorified “in a moment, in the twinkling of an eye,” then the idea of continued spiritual progression after death is unnecessary. Our salvation and glorification is not a never-ending ladder, but a gift, fully secured and perfected in Christ.

What About the Millennium?

A Latter-day Saint might respond that the millennium will provide the time for those who were alive at the time of the second coming or just didn’t have enough time in the spirit world to to finally become perfected. The thousand years of Christ’s reign function like a finishing school to prepare spirits for celestial glory.

But this idea also collides with the biblical promise of instant glorification. When Paul says that our transformation comes “in the twinkling of an eye” (1 Corinthians 15:52), he does not describe a thousand years of gradual development but an immediate transformation by God’s poer.

The apostle John makes the same point:

“Beloved, we are God’s children now, and what we will be has not yet appeared; but we know that when he appears we shall be like him, because we shall see him as he is.” (1 John 3:2)

When we see Christ, we will be like Him—not after a long millennial apprenticeship, but in the very moment of His appearing. The sight of the glorified Christ is what will complete what faith began.

This is the Christian hope: A triumphant Savior, not treadmill of self-improvement.

Birth Pains and Final Glory

Paul gives another helpful picture in Romans 8:22–23:

“We know that the whole creation has been groaning together in the pains of childbirth until now. And not only the creation, but we ourselves, who have the firstfruits of the Spirit, groan inwardly as we wait eagerly for adoption as sons, the redemption of our bodies.”

In this life, we experience the “labor pains” of sanctification, suffering, and waiting. But when Christ returns and we are raised, the child is born. The process is complete. No one expects a baby to remain in labor after delivery; birth ends the pain. Glory replaces groaning.

This analogy powerfully undercuts both purgatory and LDS post-mortal progression. If the second coming and resurrection is the moment of the “birth,” there is no need for additional spiritual gestation or painful purification. The moment of glory comes with Christ and the birth of his Kingdom.

A Glorious Finality

The biblical hope is not a shadowy afterlife of further work, but a final, decisive victory over sin and death. At Christ’s coming, the dead in Christ rise glorified (1 Thessalonians 4:16), the living are transformed, and all God’s people stand complete in His presence—thanks to Christ’s finished work.

We should reject any system, whether it’s the Catholic concept of purgatory or the LDS vision of post-moral progression that diminishes the sufficiency of Christ’s cross and the power of His return.