Hezekiah turned from Isaiah and faced God, praying:
'Remember, O God, who I am, what I've done! I've lived an honest life before you, My heart's been true and steady, I've lived to please you; lived for your approval. '
And then the tears flowed. Hezekiah wept.
Isaiah, leaving, was not halfway across the courtyard when the word of God stopped him: "Go back and tell Hezekiah, prince of my people, 'God's word, Hezekiah! From the God of your ancestor David: I've listened to your prayer and I've observed your tears. I'm going to heal you. In three days you will walk on your own legs into The Temple of God. I've just added fifteen years to your life; I'm saving you from the king of Assyria, and I'm covering this city with my shield—for my sake and my servant David's sake.'"
Isaiah then said, "Prepare a plaster of figs."
They prepared the plaster, applied it to the boil, and Hezekiah was on his way to recovery.
Hezekiah said to Isaiah, "How do I know whether this is of God and not just the fig plaster? What confirming sign is there that God is healing me and that in three days I'll walk into The Temple of God on my own legs?"
"This will be your sign from God," said Isaiah, "that God is doing what he said he'd do: Do you want the shadow to advance ten degrees on the sundial or go back ten degrees? You choose."
Hezekiah said, "It would be easy to make the sun's shadow advance ten degrees. Make it go back ten degrees."
So Isaiah called out in prayer to God, and the shadow went back ten degrees on Ahaz's sundial.
**
... and the rest of the story: Hezekiah lived fifteen more years. Just as God had promised!