We are told in the Bible that «The effectual fervent prayer of a righteous man availeth much,» or as it is put in the more meaningful Revised Standard Version, «The prayer of a righteous man has great power in its effects.» (religion-online.org)
In any event, Hezekiah spreads the written threats of the Assyrians before the LORD in the temple with fervent prayer, Isaiah utters a defiant oracle of victory, a great disaster befalls the Assyrian army, Sennacherib returns to Nineveh, and Jerusalem is saved. (religion-online.org)