The message of the prophet was short and clear: ‘You are going to die; you will not recover.’
How would we respond to such a word by a prophet? Imagine, you are in hospital, seriously ill. Someone visits you - who you know loves God dearly - and he speaks words like these. Probably, we would ignore such a message and think, or hope, that he had made it up himself. Or we would be dreadfully upset, for just imagine that he was speaking the truth…
Hezekiah accepted this word unconditionally as a word of God. He begged God for mercy and reminded God of his wholehearted devotion. He called to God, hoping that God would relent and not do as He had spoken. And God did relent, for the prophet Isaiah had barely departed when he received the order to return to Hezekiah with an entirely new message. But what was to be believed? The first message or the latter one?
If Hezekiah had not believed the first one, the latter would also have meant nothing to him. By the first word God called upon him for an even greater devotion so that, before Hezekiah died, God could give him a son to take his place on the throne. The Bible shows us in many places that those who ask God for a sign in disbelief do not receive a single sign or answer from Him, but all who truly want to serve God, may always ask for a confirmation of God’s word.
So Gideon saw fire flaring from the rock, Hezekiah saw the shadow go back, and both knew by this that God was with them and they were encouraged.