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.
Exodus 29:36
29:36 Every day you are to prepare a bull for a purification offering for atonement. You are to purge the altar by making atonement for it, and you are to anoint it to set it apart as holy.
Exodus 35:29
35:29 The Israelites brought a freewill offering to the Lord, every man and woman whose heart was willing to bring materials for all the work that the Lord through Moses had commanded them to do.