Everything eventually comes down to the authority of Scripture. A firm and honest confidence in historic Christian beliefs can come only from a prior commitment to the Bible as the Word of God.
This is as frank a précis of the intellectual dishonesty that sustains Christianity as you are likely to ever encounter. Read it again to be certain you understand what Mohler is saying here: Begin with the notion that the Bible is the word of God, and then you can have confidence in Christian teachings. That is, if you accept without evidence that the Bible is true, wise, inerrant, et cetera, et cetera, then you should have confidence in it. But if you expect the Bible to meet the corporeal standard to which you’d hold a headline in the New York Times, say, well more fool you; the Bible is never going to make any sense.
This is exactly, as my mother used to say, bass-ackward, and if this is what is taught in SBC seminaries they are committing educational fraud. Think first. Believe later.