Faithful Prayer

2 Kings 20:1-21
Hezekiah became ill and was at the point of death. Isaiah went to him and said, he is going to die. Hezekiah turned his face to the wall and prayed to the Lord, "remember, O Lord, how I have walked before you faithfully and with wholehearted devotion and have done what s god in your eyes." And Hezekiah wept bitterly.
The Lord answer through Isaiah told Hezekiah, his ill will be healed and gave Hezekiah more 15 years life. 
Hezekiah asked Isaiah a sign for this healing, "Have the shadow go back ten steps. And the Lord made the shadow go back ten steps on the stairway of Ahaz.
The messengers came with letters and a gift from King of Babylon. Hezekiah  show him all the treasure in his palace and all in his kingdom. Then Isaiah said to Hezekiah, "Hear the word of the Lord: The time will surely come when everything in your palace, and all that your fathers have stored up until this day, will be carried off to Babylon. And some of your descendants, your own flesh and blood that will be taken away, and they will become eunuchs in the palace of the king of Babylon.
Hezekiah replied, "The word of the Lord is good. Will there not be peace and security in my lifetime"
Why?
This is one of a number of Old Testament stories in which God 'changes his mind', taking a more lenient course of action in response to people's pleas.
Babylon at this time was a small state south of Assyria, looking for allies. Isaiah predicts its future power, and the fate of Judah.
A Poultice of figs: Then the routine treatment for ulcers and boils.
Hezekiah heard the words from Isaiah, he committed hi fault: proud, so he said the words of the Lord is good. And he thought these disasters will happen after his life, it is not his business.
How?
The length of life is in hands of the Lord, human being can not do anything. But wholehearted prayer sometime may change mind of the Lord. And Jesus give us the right of prayer. Faithful prayer is delight to the Lord.