Except that it DOES say that Scripture THOROUGHLY FURNISHES. What can be added to make something MORE THOROUGH, NL? Then it isn’t THOROUGH to begin with. Read the Scripture. Unless your Bible has been “edited”, and THOROUGHLY is “missing.”
Stop playing these silly little word games. It does not and never did say Scripture thoroughly furnishes. 2 Timothy 3:16-17 states that Scripture is useful (Profitable) in the furnishing (preparing).
Would you say that that verse refers to the Gospels, Paul’s own correspondence, the other letters, and to the Apocalypse?