I don't recall the name of it, it was not a big Hollywood movie or anything, and it was super low budget.
But it was some old Christian movie about what will happen to you if you don't get "saved" before the Rapture happens. I remember a song called "I wish we'd all been ready" playing. Not sure if that's the name of the song, not even positive it was actually in the movie at all, or if it was just something I heard around the same time and the memory is getting blurred.
From what I recall, it looked like it was made in the 70s.
I wish I remembered more about it. It was intended to scare the shit out of you to believe in religion. Worked on me at the time, I remember praying like a million times to make sure I did it right the night I watched it, and randomly at times for years as I remembered the scared-shitless feeling.