Jesus often prefaced his statements with the words, " it is written " meaning already written down in the old Hebrew Scriptures.
Jesus' "It is writtens" are usually followed by a simple rebuttal or dissent, not critical analysis.
Internal harmony? The Bible strikes me as a mass of contradictions.
You're assuming the authors of the revelatory scriptures were not delusional. Unless their assertions are testable, or at least falsifiable, your belief amounts to blind faith.
Why do we have such faith in the 'revelations' of ancient seers, when modern persons, making the same claims of divine inspiration, would be met with skepticism and referred for psychological assessment?[/QUOTE]
"It is written........ " shows Jesus' ability to use his logical reasoning on the old Hebrew Scriptures, thus Jesus could expound on them for us.
The apostle John wrote his gospel account ' after ' he wrote Revelation.
Just because Revelation is written in very-vivid word pictures does Not mean Revelation does Not have corresponding verses as does the rest of Scripture.
Those corresponding verses or passages show the internal harmony among the Bible writers.
Since the Bible is Not written ABC as a dictionary, then we need to study or research the Scriptures by topic or subject arrangement.
Taking one subject, or one topic, at a time helps us see there is Not a mass of contradiction but harmony in Scripture.