'Hard' in the Bible

The king's request is a very hard one, and there is no other who is able to make it clear to the king, but the gods, whose living-place is not with flesh.

O Belteshazzar, master of the scribes, because I know that the spirit of the holy gods is in thee, and no secret is too hard for thee, tell me the visions of my dream which I have seen, and the interpretation of it.

Forasmuch as an excellent spirit, and knowledge, and understanding, interpreting of dreams, and shewing of hard sentences, and dissolving of doubts, were found in the same Daniel, whom the king named Belteshazzar: now let Daniel be called, and he will shew the interpretation.

And I have had news of you, that you have the power of making things clear, and of answering hard questions: now if you are able to make out the writing and give me the sense of it, you will be clothed in purple and have a gold chain round your neck and be a ruler of high authority in the kingdom.

But {when} his heart became arrogant and his spirit became hard [so as] to act proudly, he was deposed from the throne of his kingdom and the glory {was taken away from him}.

In the third year of Cyrus, king of Persia, a secret was unfolded to Daniel, whose name was Belteshazzar; and the thing was true, even a hard work: and he had knowledge of it, and the vision was clear to him.