2 Chronicles 32:1-3

After these things, and the establishment thereof, Sennacherib king of Assyria came, and entered into Judah, and encamped against the fenced cities, and thought to win them for himself.

And when Hezekiah saw that Sennacherib was come, and that he was purposed to fight against Jerusalem,

He took counsel with his princes and his mighty men to stop the waters of the fountains which were without the city: and they did help him.