After Hezekiah had faithfully brought all the people of Judah back to the Lord, God allowed Sennacherib, King of Assyria, to come and invade Judah, to besiege their fortified cities, and to make war on Jerusalem. Eventually, Sennacherib sent his servants to Jerusalem to entice Judah to surrender.And so, they stood before the wall of Jerusalem and shouted up to the people on the wall that if they would surrender to Sennacherib they would live in peace and not die; and they also spoke against Hezekiah and against God.
But in all that they said, the people on the wall did not answer them. Meanwhile, when Hezekiah heard of their threats he tore his clothes and covered himself in sackcloth; and he sent a message to the prophet Isaiah, asking him to pray.
When Isaiah got the message, he did indeed pray; and he sent back to Hezekiah a very positive response from the Lord. Thus, the Lord said, “Do not be afraid…I will send a spirit upon him [Sennacherib] and he shall hear a rumor and return to his own land; and I will cause him to fall by the sword in his own land” (Is. 37:7).
And so it happened that Sennacherib heard that King Tirhakah of Cush (in Upper Egypt) had come out against him; and feeling trapped, like a lion in a cage, he roared out against Hezekiah, his supposed victim, by sending him a threatening letter. When Hezekiah got the letter, he read it, and then took it before the Lord in the House of the Lord; and he spread it before the Lord and prayed.
2 Kings 19:15-19 (also 2 Chronicles 32:20 and Isaiah 37:15-20)
Then Hezekiah prayed before the Lord, and said: “O Lord God of Israel, the One who dwells between the cherubim, You are God, You alone, of all the kingdoms of the earth. You have made heaven and earth. 16 Incline Your ear, O Lord, and hear; open Your eyes, O Lord, and see; and hear the words of Sennacherib, which he has sent to reproach the living God. 17 Truly, Lord, the kings of Assyria have laid waste the nations and their lands, 18 and have cast their gods into the fire; for they were not gods, but the work of men’s hands — wood and stone. Therefore they destroyed them. 19 Now therefore, O Lord our God, I pray, save us from his hand, that all the kingdoms of the earth may know that You are the Lord God, You alone.”
This prayer is a wonderful prayer, filled with praise to God. But the reason I think the prayer was most pleasing to God was because, when he prayed for deliverance, it was not merely for their own safety, but rather so that all the kingdoms of the earth may know that their God was truly the only God (v. 19), a God who was able to deliver them.
And, as it happened that night, the angel of the Lord struck dead all the soldiers in the Assyrian camp (185,000); and later King Sennacherib himself was killed by his own sons (v. 37).