God uses the same symbolism, principles and parallels to communicate to us. Sometimes there is a direct application and in others there information to be gleaned from each portion of scripture to help understand what God is saying.
An example is the picture of John eating the book(scroll) that is written on both sides in Revelation 10: 8-11 which is sweet when first eaten but then turns bitter and these same set of steps are taken by Ezekiel in Ezekiel 2:9-10; 3:1-4.
Ezekiel 2:9-10 Now when I looked, there was a hand stretched out to me; and behold, a scroll of a book was in it. (10) Then He spread it before me; and there was writing on the inside and on the outside, and written on it were lamentations and mourning and woe. 3:1-4 Moreover He said to me, “Son of man, eat what you find; eat this scroll, and go, speak to the house of Israel.” (2) So I opened my mouth, and He caused me to eat that scroll. (3) And He said to me, “Son of man, feed your belly, and fill your stomach with this scroll that I give you.” So I ate, and it was in my mouth like honey in sweetness. (4) Then He said to me: “Son of man, go to the house of Israel and speak with My words to them.
The words that Ezekiel speaks to Israel are bitter ones as you will see as you read on.
The parallel portion of scripture is:-
Revelation 10:8-11 Then the voice which I heard from heaven spoke to me again and said, “Go, take the little book which is open in the hand of the angel who stands on the sea and on the earth.” (9) So I went to the angel and said to him, “Give me the little book.” And he said to me, “Take and eat it; and it will make your stomach bitter, but it will be as sweet as honey in your mouth.” (10) Then I took the little book out of the angel’s hand and ate it, and it was as sweet as honey in my mouth. But when I had eaten it, my stomach became bitter. (11) And he said to me, “You must prophesy again about many peoples, nations, tongues, and kings.”
Notice that both John and Ezekiel were told to prophecy after eating the book (scroll).
However Ezekiel prophesied straight afterwards, but John was told that he would have to prophesy AGAIN about many peoples, nations, tongues and Kings.
This seems to imply that at some time in the future John would prophesy again outside of what was written in the book of Revelation. As implied by the 7 thunders prophecy that we dont know about. This lines up with a belief that John is one of the two witnesses mentioned in Revelation and they (John and Elijah) are going to prophesy to the world from Jerusalem for a about 3 years.
Why do I believe that John is one of the two witnesses because in Rev 1:9 it says I, John, both your brother and COMPANION in THE Tribulation and kingdom and patience of Jesus Christ, was on the island that is called Patmos for the word of God and for the testimony of Jesus Christ.
The wording implies that John will be a companion (partake) in The Tribulation. He did not say any old tribulation or in tribulations but in “The” Tribulation. He can only do this if he is one of the two witnesses. John died about 5 years after writing Revelation and did not go through The Tribulation.
Strongs word for companion is G4791 sugkoinōnos and means a co-participant: – companion, partake.
Another reason is because the Early Christian writers understood from this passage that John would be raised from the dead in the last days to proclaim the message of the seven thunders and the contents of the little scroll. (See: Hippolytus, App. xxi). To “prophesy again against…” implies John’s once again standing in opposition to these peoples, just as Ezekiel did.
This is the portion of scripture which covers the 7 thunders :-Rev 10:4 Now when the seven thunders uttered their voices, I was about to write; but I heard a voice from heaven saying to me, “Seal up the things which the seven thunders uttered, and do not write them.”
So John knows something that he will share with us when he comes back.
The implications about it being sweet and then bitter could be linked to that both these men would not have wanted to make their severe proclamations to Israel but in order to help them do it God helped them.