One example the very book of Revelations begins:
"The revelation of Jesus Christ which God gave to His servants...." rev.1:1
One can see Christ on every page....the whole Bible breaths His coming...His arrival.. His teachings, mission and life... and His one day coming again. It's all about Him.
Of course. Some are a direct revelation. Most, record historical fact prior known as tradition:
[1] Forasmuch as many have taken in hand to set forth in order a narration of the things that have been accomplished among us; [2] According as they have delivered them unto us, who from the beginning were eyewitnesses and ministers of the word: [3] It seemed good to me also, having diligently attained to all things from the beginning, to write to thee in order, most excellent Theophilus, [4] That thou mayest know the verity of those words in which thou hast been instructed. (Luke 1)
St. John , the author of the Revelation that you cite, also indicates that he knows more that he is telling in the scripture:
there are also many other things which Jesus did; which, if they were written every one, the world itself, I think, would not be able to contain the books that should be written. (John 21)It is rare exception that a direct revelation is written, like the Revelation of St. John or the Ten Commandments. Normally, the Evanglelists recorded what had been a tradition for a while.