Isaiah 38:7-8, 22

And this shall be a sign unto thee from the LORD, that the LORD will do this thing that he hath spoken; Behold, I will bring again the shadow of the degrees, which is gone down in the sun dial of Ahaz, ten degrees backward. So the sun returned ten degrees, by which degrees it was gone down.

Hezekiah also had said, What is the sign that I shall go up to the house of the LORD?