In those days was [righteous king] Hezekiah sick unto death. And the prophet Isaiah the son of Amoz came to him, and said unto him, Thus saith the Lord, Set thine house in order; for thou shalt die, and not live.

Then the king turned his face to the wall, and prayed unto the Lord, saying, "I beseech thee, O Lord, remember now how I have walked before thee in truth and with an undivided heart, and have done that which is good in thy sight." And Hezekiah wept sore.

And it came to pass, before Isaiah could get halfway out of the palace, that the word of the Lord came to him, saying, "Turn again, and tell Hezekiah the captain of my people, 'Thus saith the Lord, the God of David thy father, I have heard thy prayer, I have seen thy tears: behold, I will heal you. And I will add unto thy days fifteen years.'"
2 Kings 20:1-6