Exodus 1:11

1:11 So they put foremen over the Israelites to oppress them with hard labor. As a result they built Pithom and Rameses as store cities for Pharaoh.

Exodus 1:14

1:14 They made their lives bitter by hard service with mortar and bricks and by all kinds of service in the fields. Every kind of service the Israelites were required to give was rigorous.