"Christians may disagree over what constitutes the scariest passage in the Bible. But most would agree Jesus’s concluding words in the Sermon on the Mount rank near the top.
Not everyone who says to me, “Lord, Lord,” will enter the kingdom of heaven, but the one who does the will of my Father who is in heaven. On that day many will say to me, “Lord, Lord, did we not prophesy in your name, and cast out demons in your name, and do many mighty works in your name?” And then will I declare to them, “I never knew you; depart from me, you workers of lawlessness.” (Matt. 7:21–23)
It’s frightening to think about going to hell. It’s even more frightening to find out too late that you’re going to hell when you thought you were going to heaven. And still more frightening to think that not just a few, but “many” will have this experience. Some people think they’re Christians, they call Jesus “Lord,” they even do mighty works in his name—and yet they’re not truly saved and never were."