Exodus 9:35

Pharaoh’s heart was hardened, and he did not let the Israelites go, just as the Lord had said through Moses.

Exodus 4:21

The Lord said to Moses, “When you return to Egypt, see that you perform before Pharaoh all the wonders (miracles) which I have put in your hand, but I will harden his heart and make him stubborn so that he will not let the people go.

Treasury of Scripture Knowledge

Summary

And the heart of Pharaoh was hardened, neither would he let the children of Israel go; as the LORD had spoken by Moses.

General references

Bible References

General references

Jeremiah 34:11
But afterward they backed out [of the covenant] and made the male servants and the female servants whom they had set free return [to them], and brought the male servants and the female servants again into servitude.