2 Chronicles 32:1-5

After these things and these acts of faithfulness, Sennacherib king of Assyria came and invaded Judah and encamped against the fortified cities, thinking to win them for himself. And when Hezekiah saw that Sennacherib had come and intended to fight against Jerusalem, he planned with his officers and his mighty men to stop the water of the springs that were outside the city; and they helped him. A great many people were gathered, and they stopped all the springs and the brook that flowed through the land, saying, “Why should the kings of Assyria come and find much water?” He set to work resolutely and built up all the wall that was broken down and raised towers upon it, and outside it he built another wall, and he strengthened the Millo in the city of David. He also made weapons and shields in abundance.