Midrasch zu Schemot 14:25

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.