I've always found it hard to believe that any human being that ever lived would even begin to understand the intentions of such an entity. It would be like the ants that you've placed in an ant farm claiming to understand why they were placed in the ant farm in the first place and using that knowledge to control the other ants.

That is why most religions have a revelatory component. Hardly anyone thinks that you could figure out from first principles what God's intentions are. But he can tell you his intentions if he wants to.

I seriously doubt that you could explain your intentions to an ant (even if you wanted to, for some reason).

At the very least, if God gives us commands, we can understand the commands and obey them. I don't see how you could doubt that's possible (on the hypothesis that God does exist).