“We’re safe,” said Ford, after his first ever teleport transfer (and discovering that he and Arthur had been transported onto the bridge of an enemy space ship). “Ah,” said Arthur, “this is obviously some strange usage of the word ‘safe’ that I wasn’t previously aware of.”
—Douglas Adams, The Hitchhiker’s Guide to the Galaxy
The Spring of Gihon lies on the eastern flank of Mount Zion and, in Hezekiah’s day, was outside the walls of Jerusalem. Foreseeing a siege by the Assyrian army, and knowing that the location of the spring was the city’s weakest point, Hezekiah drove a shaft from the spring through solid rock and directed the water inside the walls to the Pool of Siloam. He then closed off the “old pool” (the Spring of Gihon) and built a second wall to enclose it. Thus Hezekiah made Jerusalem safe (2 Chronicles32:30).
Isaiah observed: “You made a reservoir between the two walls for the water of the old pool. But you did not look to its Maker, nor did you have respect for Him who fashioned it (the old pool) long ago” (Isaiah 22:11). The irony of the project was that God, who fashioned the Spring of Gihon, deliberately placing it outside the walls to made Jerusalem vulnerable to a siege!
As it turned out, Hezekiah’s fail–safe water system was wasted effort. God delivered the city in a way that had nothing to do with human endeavor. You can read the story for yourself in 2 Chronicles 32.
It comes to this: God creates weakness that we may become strong. Our physical, mental, and emotional limitations were fashioned long ago that “we might not rely on ourselves but on God” (2 Corinthians 1:9). Our limitations constrain us to cast ourselves wholly on God. In this way, his infinite resources become ours. Unqualified dependence, thus, is the only place of safety.
Paul, who was fond of paradox, put it this way: “When I am weak then I am strong” (1 Corinthians 12:10). We’re most safe when we’re most vulnerable—“obviously some strange usage of the word safe,’” I must say.
 The Old Pool and the vertical shaft that rose from it were, in fact, the means by which David gained access to the old Jebusite citadel of Jerusalem when it was in the hands of the Canaanites (2 Samuel 5:6-10).
 Chris and Ted Stewart, in their book, The Miracle of Freedom: Seven Tipping Points that Saved the World, make this an event that saved Western Civilization from paganism.