Which, I'll point out, most Christians verifably don't have. The number of amputees pretty well proves that (and the number of Christians fooled by placebo also does). It's an assumption that you need less faith to be saved than to move mountains. I know, I know, it's also 'faith' that you need less faith. But it's an assumption. Self-entitled cockiness isn't faith.You hit the nail right on the head. Faith is what saves. Even if it is the size of a mustard seed if it is genuine it saves.
Not so sure that the Bible is a tool to lead people astray. I've been seeing a lot of this type of discussion lately. Jesus said of the last days to be wary of deception. (I'm paraphrasing)
I don't believe that it's a tool designed to lead people astray (I like the thing a Rabbi said once, it's not so much a tool to understand God, it's a record of people's best-efforts to understand God), I just say that there's more evidence that it is designed thusly than it being legit Holy.
An anonymous author quotes Jesus as having said that. You cannot definitely say "Jesus said that". I mean, it's the same book where a (different) anonymous author claims that God wiped out humanity with a Flood. Heck, the same author who quotes Jesus tell us a story about Jesus's temptation. We know that the authors included 'facts' that they didn't actually have evidence for. The book you're holding was built by fallible people after Jesus was gone, for all you know, that's where the deception occurred.
But, as a tool designed to lead people astray, it's not like the average Bible-believer has faith sufficient to move mountains. And the average Bible-believer has believed really awful things about God (without evidence) because of the Bible. I assume it's people's best-effort. But if we want to assume the existence of supernatural forces, there's more evidence that it was built by a mischievous spirit than a good one. As far as I can tell, we've swapped real faith in God for a faith in the Bible.