When God sent the plague of the firstborn...all the firstborn Egyptians went to speak to their fathers and said "Everything which Moses has said has come true, don't you want us to live? Let us get the Hebrew slaves out of our homes now. Otherwise we are dead." The fathers answered "even if all of Egypt dies they are not leaving." All the firstborn gathered in front of Pharaoh and screamed "Please remove the Hebrews, because of them evil will befall us and you." Pharaoh said to his servants, "Remove the protesters and break their knees." What did the young Egyptians do? Each took a sword and killed his father.

(Translation by Rabbi Daniel Brenner from Midrash Tehillim 136:6, Tanchuma Bo 18) 

haggadah Section: Maggid - Beginning
Source: Rabbi Daniel Brenner