Aye; there's the rub; for folks CANNOT 'know' what they are being saved from.
They have to take THAT on 'faith'; too!
Naw, the bible sez what it is. It calls it the “second death”. Jesus explained it. It’s even mentioned in Genesis.
To understand the explanations, though, one needs to put themself into the mind of the readers of the scripture at the time they were penned. It’s really simple. Ecclesiastes even discusses it.