A close LDS friend of mine and I were discussing this last night in the context of some statements by past LDS leaders.
So here's the question. Are there any categories of things that a true prophet of God cannot teach without being chastised by God and directed to publicly retract it for the sake of God's people? (That is, perhaps a prophet could assert it - maybe - but God would confront him in order to correct him so that the people of God would not be led astray.)
And a follow-up question: if the set of things that a true prophet cannot teach is either empty or relatively small, how ought a follower regard what the prophet says? And what benefit is there in having a prophet anyway?