Isaiah 38:7-8, 22

“This shall be the sign to you from the LORD, that the LORD will do this thing that He has spoken: Listen carefully, I will turn the shadow on the stairway [denoting the time of day] ten steps backward, the shadow on the stairway (sundial) of Ahaz.” And the sunlight went ten steps backward on the stairway where it had [previously] gone down.

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