Exodus 12:40-42

40Now the length of time the Israelite people lived in Egypt Masoretic Text; Samaritan Pentateuch and Septuagint Egypt and Canaan was 430 years. 41At the end of the 430 years, to the very day, all the LORD ’s divisions left Egypt.

42Because the LORD kept vigil that night to bring them out of Egypt, on this night all the Israelites are to keep vigil to honor the LORD for the generations to come.