“staff of bread.” “Bread” was a common idiom for food. “Bread” came to be used by metonymy for food in general because bread was the main food in the culture and a staple of life. Bread was indeed the staff upon which the people leaned for food, and in literature it is sometimes referred to as the “staff of life.” Here it is the “staff of bread” (cp. Ps. 105:16; Ezek. 4:16; 5:16).
[See figure of speech “metonymy.”]