Albert Barnes Commentary Ezekiel 4:16

"Moreover he said unto me, Son of man, behold, I will break the staff of bread in Jerusalem: and they shall eat bread by weight, and with fearfulness; and they shall drink water by measure, and in dismay:" — Ezekiel 4:16 (ASV)

The staff of bread - Bread is so called because it is that on which the support of life mainly depends.

With astonishment - With dismay and anxiety at the calamities which are befalling them.