Thus saith the Lord,… I have heard thy prayer. According to the author of Kings, the full message sent to Hezekiah was, "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 the Lord.
And I will add unto thy clays fifteen years; and I will deliver time 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" (2 Kings 20:5, 2 Kings 20:6).
The words in italics are additional to those here reported by Isaiah. Fifteen years. This was doubling, or rather more than doubling, the length of Hezekiah's reign, and allowing him a length of life exceeding that of the great majority of the kings of Judah, who seldom attained the age of fifty.
Hezekiah lived to be fifty-four.