Support And Collapse
The idiom works because bread was real support.
In agrarian societies, grain stores could stand between a city and death. The staff image is not decorative. It names dependence.
Isaiah uses a related phrase, “stay of bread” and “stay of water.”1 Psalm 104 says bread strengthens the human heart.2
These texts do not make bread divine. They make bread load-bearing.
Load-bearing means a structure depends on it. If it fails, other things fall.
That is why famine or siege can become theological crisis. When bread breaks, life feels unsupported. The staff snaps in the hand.
The double sense matters. The Bible knows bread’s strength. It also knows that strength can collapse.
Related sections: The Idiom That Breaks; Hebrew Greek Latin English.