What did the Gospel writers believe that the miracles showed?

Another answer from our community: The Bible makes no clear cut distinction between the natural and supernatural. In the "natural" event the Bible views God as working providentially; whereas, in the miraculous, God works in striking ways to call attention to Himself or His purposes.

"Sign" in the New Testament is used of miracles taken as evidence of divine authority. "Wonders" in Greek denotes something unusual that causes the beholder to marvel. Whereas a sign appeals to the understanding, a wonder appeals to the imagination.