Isaías 19:19 Midrash: Mekhilta DeRabbi Yishmael & Mekhilta DeRabbi Shimon Ben Yochai

(Exodus 13:17) "And it was, when G–d sent ("shalach") the people": "sending" in all places is accompaniment, viz. (Genesis 18:16) "And Abraham went with them to send them," (Ibid. 26:31) "And Israel sent them." The mouth (of Pharaoh) that said (Exodus 5:2) "Israel, too, I will not send," it is that (mouth) which said (Ibid. 10:10) "I will send you and your children." How was he rewarded for this? (Devarim 23:8) "You shall not abominate an Egyptian." The mouth which said (Exodus 5:2) "I do not know the L–rd," it is that (mouth) which said (Ibid. 14:25) "I will flee from before Israel, for the L–rd wars for them against the Egyptians." How was he rewarded for this? (Isaiah 19:19) "On that day there will be an altar to the L–rd in the midst of the land of Egypt and a pillar at its border to the L–rd." The mouth which said (Exodus 5:2) "Who is the L–rd that I should hearken to His voice," it is that mouth which said (Ibid. 9:27) "the L–rd is the Tzaddik, and I and my people are the wicked" — wherefore He gave them a place for burial, as it is written (Ibid. 15:12) "You inclined Your right hand — the earth swallowed them up."

Your flocks: "Your flocks come also from mine!" Your herds: "Your herds come also from my ministers!" Take [them], as you said, and begone!: Your prediction has been fulfilled! "Moses said, “You yourself must provide us with sacrifices and burnt offerings to offer up to the LORD our God" (Exodus 10:25) And may you bring a blessing upon me also!: Even women and children. Another interpretation: "And may you bring a blessing upon me also." (Exodus 12:32) From here you say that Pharaoh knew that he was lacking in prayer, and God does not forgive someone until he has persuaded his neighbor [to forgive him as well]. What reward did he take for this? -- "In that day, there shall be an altar to the LORD inside the land of Egypt" (Isaiah 19:19) The mouth that said, "Who is the LORD that I should heed Him [and let Israel go]?" (Exodus 5:2) is [also] the mouth that said, "The LORD is in the right [and I and my people are in the wrong.]" (Exodus 9:27) What reward did he take for this? -- "You shall not abhor an Egyptian, for you were a stranger in his land." (Deuteronomy 23:8) The mouth that said, "I will pursue, I will overtake, I will divide the spoil," (Exodus 15:9) is [also] the mouth that said, "Let us flee from the Israelites, [for the LORD is fighting for them against Egypt.]" (Exodus 14:25) What reward did he take for this? -- "You put out Your right hand, The earth swallowed them." (Exodus 15:12) They merited to be buried, that beast and birds would not eat them.