Exodus 1:8-11

8Then a new king, to whom Joseph meant nothing, came to power in Egypt. 9“Look,” he said to his people, “the Israelites have become far too numerous for us. 10Come, we must deal shrewdly with them or they will become even more numerous and, if war breaks out, will join our enemies, fight against us and leave the country.” 11So they put slave masters over them to oppress them with forced labor, and they built Pithom and Rameses as store cities for Pharaoh.