What does Exodus 12:15 mean?
Part of God's preparation to bring Israel out of Egyptian slavery (Exodus 1:8–14) was to make the nation ready for travel on the night of the first Passover (Exodus 12:8–11). This included preparing "unleavened" bread. Leavening is a rising agent, such as yeast. Cooking dough without yeast—or leaven—is much faster than waiting for it to expand and rise. When the Lord's final plague strikes (Exodus 11:4–6), Egyptians will demand Israel leave immediately (Exodus 12:33). The nation will begin their march out of Egypt carrying unleavened bread (Exodus 12:39).The Lord has noted that Passover was to become a permanent celebration for the nation of Israel (Exodus 12:14). Following this would come a "Feast of Unleavened Bread" (Exodus 12:17). God's people would remember their liberation by eating unleavened bread for a week. Further, they were to scour their homes to remove all leaven—all yeast or similar rising agents—as a symbolic cleansing from sin (1 Corinthians 5:8). These instructions will be repeated for emphasis (Exodus 12:19–20).
Those who defied this requirement would be "cut off" from the nation of Israel. At the very least, this meant being excluded from covenant promises (Genesis 17:14). It implied being shunned and rejected from the camp and the community (Numbers 9:13). In an ancient world where people greatly depended on others for survival, this could easily lead to death. In some situations, being "cut off" seems to have included an explicit sentence of death (Leviticus 20:1–3).
Exodus 12:1–28 records the Lord's instructions for the first observation of Passover. The Israelites are to sacrifice lambs and prepare a specific set of foods. These must be eaten while dressed for travel. The lamb's blood is to be collected at the threshold of the door and then applied to the top and side posts. On that first Passover, God will kill the firstborn of Egypt (Exodus 11:4–6). Houses marked with the lamb's blood will be spared: God's judgment will "pass over" them without harm (Exodus 11:7). This event will establish a new start for Israel's yearly calendar. It is to be commemorated every year by using various symbolic elements. Future generations are to be carefully taught the meaning of these things.
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.
