Psalm 46

"There is a river, the streams whereof shall make glad the city of God." Jerusalem has no river. It has one spring — the Gihon, in the valley outside the wall — and that was the city's weak point in a siege. Hezekiah's answer was to cut a tunnel more than 1,700 feet through solid rock to bring the water inside the walls, and the workmen left an inscription at the meeting point describing the moment the two crews broke through to each other. The tunnel still carries water. A besieged city with water inside is a city that can wait.

"Though the earth be removed, and though the mountains be carried into the midst of the sea; though the waters thereof roar and be troubled" is the language of total collapse — the most fixed things a person could name going into the least fixed thing. Set against that, a quiet stream running under a city.

"He breaketh the bow, and cutteth the spear in sunder; he burneth the chariot in the fire." Captured weapons were routinely destroyed after a battle so they could not be turned around and reused, and the burning of chariots is recorded in Israel's own campaigns.

The heading "upon Alamoth" most likely indicates a high vocal range — the word is related to young women — matching the Chronicles' note that some Levites were appointed to play psalteries on Alamoth.