As necessary as familiarity with the Old Testament is to an understanding of the book of Revelation, it is not sufficient. We must add to it a right relationship with the ultimate Author of the book lest we fall prey to the condition of Israel in Isaiahs day:
Pause and wonder! Blind yourselves and be blind! They are drunk, but not with wine; they stagger, but not with intoxicating drink. For the LORD has poured out on you the spirit of deep sleep, and has closed your eyes, namely, the prophets; and He has covered your heads, namely, the seers. The whole vision has become to you like the words of a book that is sealed, which men deliver to one who is literate, saying, Read this, please. And he says, I cannot, for it is sealed. Then the book is delivered to one who is illiterate, saying, Read this, please. And he says, I am not literate. Therefore the Lord said: Inasmuch as these people draw near with their mouths and honor Me with their lips, but have removed their hearts far from Me, and their fear toward Me is taught by the commandment of men, therefore, behold, I will again do a marvelous work among this people, a marvelous work and a wonder; for the wisdom of their wise men shall perish, and the understanding of their prudent men shall be hidden. (Isa. Isa. 29:9-14)We must recognize that our wisdom depends upon God and He will not share intimacy of understanding with those who feign a devotion or whose motivations are impure. Ultimately, it is not knowledge we desire, but God Himself.
And you will seek Me and find Me, when you search for Me with all your heart. (Jer. Jer. 29:13)