What does Exodus 12:47 mean?
For those following Israel's covenant relationship to the Lord (Genesis 17:10–14), observing Passover was not optional. The phrase "congregation of Israel" is used frequently in the Old Testament in relation to Israel. This is meant to emphasize the communal, family nature of God's chosen people (Deuteronomy 14:2). In a broad sense, it means every single person in Israel (Leviticus 4:13; Numbers 16:9). Those not native to the nation could still participate, if they complied with the covenant (Genesis 17:10–14; Exodus 12:43–45, 48)."Keeping" the Passover means following the Lord's instructions (Exodus 12:21–28) for remembrance. God finished His work (Exodus 3:19–20) of breaking the hold of Egyptian slavery (Exodus 1:11–14) over Israel using a terrible plague (Exodus 11:4–6). Those who followed His commands that night were spared (Exodus 12:12–13) as judgment would "pass over" their homes. Israel was commanded to remember this for all time (Exodus 12:14).
Exodus 12:43–51 expands on future remembrances of Israel's exodus from Egyptian slavery (Exodus 12:33–42). God connects Passover rituals to the identifying rite of circumcision (Genesis 17:9–11). Only those who identify with the Lord through circumcision can participate. Israel has obeyed these commands and is now leaving Egypt in a single massive group. Instructions about festivals will be provided in the next chapter.
Israel is to realign their calendar to begin with the current month. They receive instructions to prepare a special meal. This includes sacrificing lambs and applying their blood to the doorway of each home. Following these instructions will cause God's wrath to "pass over" that house. Egypt's firstborn are killed and they demand Israel leave immediately. The people quickly gather their belongings and march out in a single massive group. These events are to be remembered with festivals to be celebrated for all time.
