GOD has hidden lots of truth before. For example, GOD hid what was undoubtedly the biggest truth of them all, that being that He Himself would incarnate. This truth can be found all over the OT but it was hidden from all the Jewish scholars until He actually came and showed it to us. (Luke 24:27) And Jesus told us that there was still some more truth to be revealed someday. Most Christians don't think about this too much, but it's true nonetheless. And, if you want, every verse interpretation can be discounted somehow and discarded because that is the way truth is.
Daniel 12:9 And he said, Go thy way Daniel: for the words are closed up and sealed till the time of the end. 10 Many shall be purified, and made white, and tried; but the wicked shall do wickedly: and none of the wicked shall understand, but the wise shall understand. Therefore, we can say with assurance that this verse bears witness that there will be an unsealing, disclosing or revealing at the time of the end.
Therefore I suggest that, in the end times, we will be given a new understanding, that is, an illumination which has been sealed previously.
Zechariah 5:1 I looked again—and there before me was a flying scroll! 2 He asked me, “What do you see?” I answered, “I see a flying scroll, thirty feet long and fifteen feet wide.” 3 And he said to me, “This is the curse that is going out over the whole land; for according to what it says on one side, every thief will be banished, and according to what it says on the other, everyone who swears falsely will be banished. 4 The Lord Almighty declares, ‘I will send it out, and it will enter the house of the thief and the house of him who swears falsely by my name. It will remain in his house and destroy it, both its timbers and its stones.’” Since it is a book (scroll) it would probably contain some ideas of an unearthly (previously unrevealed) nature. Its measurement "just happens" to match the holy place of GOD's temple, so it would probably be a holy book. And its holy message will have a profound effect on some people, for it obviously has some bad news:
Kiel(#2) comments: “The roll therefore symbolised the curse which will fall upon sinners throughout the whole land, consuming them with their houses, and thus sweeping them out of the nation of GOD.” (In other words, Armageddon.)
Cursed by the message of a scroll (book) - don't think we've seen that yet...
Isaiah 11:9 - For the earth shall be full of the knowledge of the LORD, as the waters cover the sea. Is our knowledge this full, let alone the whole earth? Is this just hyperbole you can ignore? Or does something new this way come...?
Jeremiah 23:20 - The anger of the LORD shall not return, until HE have executed, and till HE have performed the thought of HIS heart. In the latter days ye shall consider it perfectly. We will understand perfectly HIS thoughts. So much for those who claim HE is too far above us to know anything about HIM, eh?