What does Exodus 1:9 mean?

Pharaoh describes a growing problem for his Egyptian people. This involves two specific areas. First, Israeli numbers had grown over the centuries from seventy to "filling" the land where they had settled (Exodus 1:1–7). Later verses indicate that Israel would continue to grow, despite oppression (Exodus 1:12). Second, Egypt's king worries that by sheer numbers, the Israelites could form an army and threaten the Egyptians in a war. Or, more likely, they might be convinced to join the enemies of the Egyptians to defeat them in an invasion (Exodus 1:10).

The first resolution attempted by Egypt's king is forced labor (Exodus 1:11). The enslaved Israelites are noted for building two cities: Pithom and Raamses (Exodus 1:11). Both were south of the capital of Zoan along tributaries of the Nile River leading to the mouth of the Mediterranean Sea. The exact meaning of "store cities" is uncertain, but it is clear these were some kind of supply areas used by the Egyptians. They may have served as a continuation of Joseph's food storage efforts from the seven years of plenty when all Egyptians began the tradition of storing part of their grain.