“...invoked Scripture...both understood its supreme authority...”
Jesus Himself is the Supreme Authority.
Of course, but the context ("for it is written") was that of the express transcendent revelation of His Truth, and the Lord Himself established His Truth claims upon Scriptural substantiation in word and in power.
Ok fine. And He was the Word made flesh too.
Did He argue == "listen to me, I am the Supreme Authority"?
Not at all.
He did not in that instance which was under discussion, cite his own personal authority, or 'position of' authority.
It's just the way it is.