Oliver Cowdery wants to be able to do what Joseph Smith does. So Joseph gets a handy divine revelation for him.
God puts the Bland in Blandishment
First God tries to wave him off the notion of translation, explaining that Oliver has the spirit of revelation so that he can, like, know things and evade enemies and stuff. He butters Oliver up a bit by adding, in verse 3, that this is the same gift that Moses had. Just to keep Oliver appeased, he also mentions that he has the gift of Aaron too, which I'd normally expect to be a reference to the Aaronic Priesthood but for the fact that it won't be restored for another month or so. So it could be a reference to Aaron's public speaking ability, which supplemented a weakness of the prophet Moses. Is God saying that Joseph is a poor orator and that Oliver is destined to be the prophet's press secretary?
It's difficult to say, especially since the most likely explanation isn't really supported by the subsequent history in which Joseph addressed the church directly—tons of times—without requiring a sidekick to improve his diction or to elevate his elocution. This means God is being pretty vague about what makes these two gifts distinct from each other. Maybe he was hoping Oliver would be so honored to be compared to not one but two great Biblical figures that he wouldn't realize both of these revelatory gifts he supposedly possessed sounded like the same thing.
God Puts the Mess in Mixed Messaging
This weirdness comes through in verse 10:
Remember that without faith you can do nothing; therefore ask in faith. Trifle not with these things; do not ask for that which you ought not.
Without faith you can do nothing? What a dick comment. None of this make-weak-things-become-strong pussyfooting—you're basically worthless when you're faithless.
And the advice not to ask for that which he ought not is even more insidious. I wonder if Joseph was manipulating Oliver here by giving him vague threats that he has no guarantees of avoiding. God isn't saying, "Don't ask for A, B, or C, but D is cool." It's phrased in such a way that you have to wonder if, whenever Oliver got ambitious, he'd stop himself, quaking in his boots, because he didn't want to piss God off for asking the wrong thing based on these nebulous guidelines for inquiries. After all these wonderful words and grand promises, Joseph is trying to make sure that, now that Oliver is appeased and motivated, he's also going to be restrained and tractable.
And then perhaps to end on a positive note of appeasement and motivation, God tells Oliver in verse 11 that he'll be able to translate ancient records according to his faith. God is sending some really mixed signals here, and it sure seems manipulative.