When Hezekiah (about 714-686 BC) succeeded Ahaz, he also disregarded Isaiah's advice and became involved in a coalition with Babylonia and Egypt against Assyria. Sennacherib of Assyria moved against Jerusalem in 701 BC. It was at this time that Hezekiah constructed the Siloam Tunnel to bring water from the Spring of Gihon into the city of Jerusalem (2 Chr. 32:30). But then something very strange happened. Somehow, miraculously the Assyrians withdrew from attacking Jerusalem after suffering heavy losses, perhaps from a plague. History leaves a big question mark at this point. Why didn't Sennacherib build a seige mound against Jerusalem and completely conquer it? The Bible reveals something very interesting:

Isa 37:33-38 "Therefore thus says the LORD concerning the king of Assyria: 'He shall not come into this city, nor shoot an arrow there, nor come before it with shield, nor build a siege mound against it. By the way that he came, by the same shall he return; and he shall not come into this city,' says the LORD. 'For I will defend this city, to save it for My own sake and for My servant David's sake.' "Then the angel of the LORD went out, and killed in the camp of the Assyrians one hundred and eighty-five thousand; and when people arose early in the morning, there were the corpses-- all dead. So Sennacherib king of Assyria departed and went away, returned home, and remained at Nineveh. Now it came to pass, as he was worshiping in the house of Nisroch his god, that his sons Adrammelech and Sharezer struck him down with the sword; and they escaped into the land of Ararat. Then Esarhaddon his son reigned in his place."