Isaiah 38:5-8

5“Go and say to Hezekiah, ‘For the Lord, the God of David your father says this, “I have heard your prayer, I have seen your tears; listen carefully, I will add fifteen years to your life.

6I will rescue you and this city from the hand of the king of Assyria; and I will defend this city [Jerusalem].” ’

7“This shall be the sign to you from the Lord, that the Lord will do this thing that He has spoken:

8Listen 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.