Exodus 1:11-13

11 And they set taskmasters over them to afflict them with their burdens. And they built treasure cities for Pharaoh, Pithon and Raamses.

12 But the more they afflicted them, the more they multiplied and grew. And they were grieved because of the sons of Israel.

13 And the Egyptians made the sons of Israel serve with harshness.