This is going to throw a spanner in the works for some, but the book of Daniel is the only book of all the books of scriptures that was sealed to the end. It prophesied of the coming Messiah who John witnessed in the flesh in his days, and it prophesied of
the judgment of Jerusalem and end of the old covenant/sacrifices. Remember this is about "finishing" the mystery of God. So what is that mystery? And what was Jesus talking about when He said "it is finished" on the cross. Do a word search of "mystery of God". And remember the gospel (and many prophecies) is to the Jew FIRST, then the Gentile. So we need to at least look at it first from Israel's point of view back then.
Dan 8:11-14
Yea, he magnified
himself even to the prince of the host, and by him the daily
sacrifice was taken away, and the place of his sanctuary was cast down.
And an host was given
him against the daily
sacrifice by reason of transgression, and it cast down the truth to the ground; and it practised, and prospered.
Then I heard one saint speaking, and another saint said unto that certain
saint which spake, How long
shall be the vision
concerning the daily
sacrifice, and the transgression of desolation, to give both the sanctuary and the host to be trodden under foot?
And he said unto me, Unto two thousand and three hundred days; then shall the sanctuary be cleansed. (by fire and judgment!)
Dan 8:19
And he said, Behold, I will make thee know what shall be in the last end of the indignation: for at the time appointed the end
shall be.
Dan 9:26
And after threescore and two weeks shall Messiah be cut off, but not for himself: and the people of the prince that shall come shall destroy the city and the sanctuary; and the end thereof
shall be with a flood, and unto the end of the war desolations are determined.
Dan 9:27
And he shall confirm the covenant with many for one week: and in the midst of the week he shall cause the sacrifice and the oblation to cease, and for the overspreading of abominations he shall make
it desolate, even until the consummation, and that determined shall be poured upon the desolate. (Remember Jesus prophesying that their house would be left to them desolate.)
Dan 8:17
So he came near where I stood: and when he came, I was afraid, and fell upon my face: but he said unto me, Understand, O son of man: for at the time of the end
shall be the vision.
Dan 11:35
And
some of them of understanding shall fall, to try them, and to purge, and to make
them white,
even to the time of the end: because
it is yet for a time appointed.
Dan 11:40
And at the time of the end shall the king of the south push at him: and the king of the north shall come against him like a whirlwind, with chariots, and with horsemen, and with many ships; and he shall enter into the countries, and shall overflow and pass over.
Dan 12:4
But thou, O Daniel, shut up the words, and seal the book,
even to the time of the end: many shall run to and fro, and knowledge shall be increased.
Dan 12:9
And he said, Go thy way, Daniel: for the words
are closed up and sealed till the time of the end.
John was living in the time of the end of Jerusalem and temple sacrifices. God putting an end to it all. Only the Lamb that had been slain was worthy to unseal that scroll (ie, to unleash and pour out those judgments/wrath!) After Jesus had left this world, Jerusalem and temple worship proceeded to turn into a complete horror show and was filling up the wrath of God, as well as most cruelly persecuting the early church....studious types can look into what Josephus recorded about these things.