Isaiah 38:7-8, 22

And this shall be the sign unto thee from Jehovah, that Jehovah will do this thing that he hath spoken: behold, I will cause the shadow on the steps, which is gone down on the dial of Ahaz with the sun, to return backward ten steps. So the sun returned ten steps on the dial whereon it was gone down.

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