E.M.Bounds

The message of God to Hezekiah was a warning of death, as can be seen in this passage from Isaiah:
Thus saith the Lord, Set thine house in order: for thou shalt die, and not live. Then Hezekiah turned his face toward the wall, and prayed unto the Lord, and said, Remember now, O Lord, I beseech thee, how I have walked before thee in truth and with a perfect heart, and have done that which is good in thy sight. And Hezekiah wept sore. Then came the word of the Lord to Isaiah, saying, Go, and say to Hezekiah, Thus saith the Lord, the God of David thy father, I have heard thy prayer, I have seen thy tears: behold, I will add unto thy days fifteen years.(Isa. 38:1–5)
Hezekiah’s prayer changed God’s purpose, and fifteen years were added to his life.

The Syrophenician woman (see Mark 7:24–30), the importunate 1 widow (see Luke 18:1–7), and the friend at midnight (see Luke 11:5–10) are wonderful lessons of what dauntless prayer can do in mastering or defying conditions, in changing defeat into victory and triumphing in the regions of despair.
All these people of God knew how to pray and how to prevail in prayer. Their faith in prayer was no passing attitude that changed with the wind or with their own feelings and circumstances; they were confident that God always heard and answered, that His ear was always open to the cry of His children, and that the power to do what was asked of Him was equal to His willingness. Thus, strong in faith and in prayer, they
subdued kingdoms, wrought righteousness, obtained promises, stopped the mouths of lions, quenched the violence of fire, escaped the edge of the sword, out of weakness were made strong, waxed valiant in fight, turned to flight the armies of the aliens.(Heb. 11:33–34)

Everything was possible to the men and women who knew how to pray, and it is still possible today. Prayer, indeed, opened a limitless storehouse, and God’s hand withheld nothing. Prayer introduced those who practiced it into a world of privilege, and brought the strength and wealth of heaven down to the aid of finite man. What rich and wonderful power they had who had learned the secret of victorious approach to God! With Moses it saved a nation; with Ezra it saved a church. (See Ezra 1:1–4 and Ezra 7–9.)
And yet, strange as it seems when we contemplate the wonders of which God’s people had been witnesses, they became slack in prayer. The mighty hold upon God, which had so often struck awe and terror into the hearts of their enemies, lost its grip.