And the Lord said to Moses: Now thou shalt see what I will do to Pharao. For by a mighty hand shall he let them go, and with a strong hand shall he cast them out of his land.
And the Lord said to him as he was returning into Egypt: See that thou do all the wonders before Pharao, which I have put in thy hand. I shall harden his heart, and he will not let the people go.
And Pharao sent to see: and there was not any thing dead of that which Israel possessed. And Pharao's heart was hardened, and he did not let the people go.
And his heart was hardened, and the heart of his servants: and it was made exceeding hard. Neither did he let the children of Israel go, as the Lord had commanded by the hand of Moses.
And Moses and Aaron did all the wonders that are written, before Pharao. And the Lord hardened Pharao's heart: neither did he let the children of Israel go out of his land.
For when Pharao was hardened, and would not let us go, the Lord slew every firstborn in the land of Egypt, from the firstborn of man to the firstborn of beasts: therefore I sacrifice to the Lord all that openeth the womb of the male sex, and all the firstborn of my sons I redeem.