2 Kings 20:5-9

Turn back, and say to Hezekiah the prince of my people, Thus saith Jehovah, the God of David thy father, I have heard thy prayer, I have seen thy tears: behold, I will heal thee; on the third day thou shalt go up unto the house of Jehovah.

And I will add unto thy days fifteen years; and I will deliver thee and this city out of the hand of the king of Assyria; and I will defend this city for mine own sake, and for my servant David’s sake.

And Isaiah said, Take a cake of figs. And they took and laid it on the boil, and he recovered.

And Hezekiah said unto Isaiah, What shall be the sign that Jehovah will heal me, and that I shall go up unto the house of Jehovah the third day?

And Isaiah said, This shall be the sign unto thee from Jehovah, that Jehovah will do the thing that he hath spoken: shall the shadow go forward ten steps, or go back ten steps?