2 Kings 20:8-9

8Hezekiah said to Isaiah, “What will be the sign that the Lord will [completely] heal me, and that I shall go up to the house of the Lord on the third day?”

9Isaiah said, “This will be the sign to you from the Lord, that He will do the thing that He has spoken: shall the shadow [indicating the time of day] go forward ten steps, or go backward ten steps?”