My reading is that the prophets weren't speaking their own words but only whatever God told them to say.
As I said in post #587, the Greek for 2 Peter 1:20 (found here - also at "BibleHub", literally says the following:
"This first knowing that any prophecy of scripture of its own interpretation not is"Various Bible translation teams have come up with many different interpretations for that text, and in that same post #587 on this thread, I included some of the more common Protestant Bible translations of that particular text, as shown again here:
Some Common Protestant Bible Versions Of "2 Peter 1:20"
"Knowing this first, that no prophecy of scripture is of private interpretation." - 2 Peter 1:20 - American Standard Version (ASV)
"Knowing this first, that no prophecy of the scripture is of any private interpretation." - 2 Peter 1:20 - King James Version (KJV)
"But know this first of all, that no prophecy of Scripture is a matter of ones own interpretation." - 2 Peter 1:20 - New American Standard Bible (NASB)
"First of all you must understand this, that no prophecy of scripture is a matter of ones own interpretation." - 2 Peter 1:20 - Revised Standard Version (RSV) - Protestant Edition)