1. When we earnestly pray God will answer our prayers.
Jam 5:16 Confess faults to one another, and pray for one another, that you may be healed. The effectual fervent prayer of a righteous one avails much.
2. We have to pray according to God's Will, not to change God's Will.
1Jo 5:14 And this is the confidence that we have toward Him, that if we ask anything according to His will, He hears us.
3. Normally God's Will shall not change.
Job 23:13 But He is in one mind, and who can turn Him? Yea, what His soul desires, He does it.
Psa 33:11 The counsel of Jehovah stands forever, the thoughts of His heart to all generations.
4. But certain cases God's Will, changed because of fervent prayers, example is King
2Ki 20:1-6 In those days Hezekiah was sick to death. And the prophet Isaiah the son of Amoz came to him and said to him, So says Jehovah, Set your house in order, for you shall die and not live. And he turned his face to the wall and prayed to Jehovah, saying, O Jehovah, I pray, O Jehovah, remember now how I have walked before You in truth and with a sincere heart, and have done good in Your sight. And Hezekiah wept with a great weeping. And it happened, Isaiah had gone out into the middle of the court, the Word of Jehovah came to him saying, Return again and tell Hezekiah the leader of My people, So says Jehovah, the God of David your father, I have heard your prayer, I have seen your tears. Behold, I will heal you. On the third day you shall go up to the house of Jehovah. And I will add fifteen years to your days. And I will deliver you and this city out of the hand of the king of Assyria. And I will defend this city for My own sake, and for My servant David's sake.