Divine Providence often guides the course of history through the forces of nature. A famine is not a random disaster, but rather a deliberate tool used by God. He decreed this period of starvation to set off a specific chain of events that would lead Jacob and his family down to Egypt. This descent was a necessary stage of purification—a refining process in an iron furnace—designed to prepare them to fulfill the covenant and inherit the land promised to Abraham [מלבי״ם].
God commanded the famine to arrive, acting as if He were calling it to step forward and carry out a specific mission [רד״ק, אבן עזרא, מלבי״ם, מאירי]. This divine summons, announced ahead of time through Pharaoh's dreams, was orchestrated to set the causes of the exile into motion [רש״י, רד״ק, מלבי״ם]. The starvation was directed primarily at the land of Canaan, the home of the forefathers [אבן עזרא, מאירי]. God dismantled the economic foundation of Canaan, and subsequently brought severe hunger to Egypt as well [ביאור שטיינזלץ, מאירי].
The severity of this event is illustrated through the imagery of a shattered staff of bread. A staff serves as a walking stick, acting as a symbol of support and stability. Just as a person leans on a cane to walk, human beings rely on basic sustenance to survive [רד״ק, מצודת ציון, ביאור שטיינזלץ]. By breaking this staff, God completely cut off and withheld every reliable source of food from the land [רד״ק, מצודת דוד, מאירי]. Furthermore, this devastation went beyond a mere failure of new crops to grow. Even the healthy grain that people had carefully gathered and stored in warehouses ahead of time, hoping to rely on it, rotted away and was entirely destroyed [אלשיך].