What does the bible say about trying to use untruths and logical fallacies to "prove" the bible is true?

Not like Christians have ever read the Bible in the first place. There is, however, a long-standing tradition in Christianity that lying is OK as long as you're doing it on Christianity's behalf. In fact, "doing terrible thing X for Jesus" is OK no matter what terrible thing X is, and that includes theft, arson, slavery, rape and murder. In fact, the only things that are so terrible that you can't do them on Jesus' behalf are engaging in same-sex intercourse and voting Democrat.