This is another thing I like to post every Easter: Jesus raising Lazarus from the dead, in The Greatest Story Ever Told. The emotional impact of this scene speaks for itself.
Why did Jesus do miraculous works? So that they would be a witness to whom and what He is. We have the Scriptures, we have the works, we have eyewitness testimony, and we have the Holy Spirit: Jesus is the Son of God, the Savior.
And here is where the Bible parts company with pious pagan fictions: John 11: 39:
Jesus said, Take ye away the stone. Martha, the sister of him that was dead, saith unto him, Lord, by this time he stinketh: for he hath been dead four days.
This kind of realism would not enter fiction for centuries yet to come.