What does Exodus 12:41 mean?
When God made a covenant with Abram—later named Abraham (Genesis 17:5)—it included a prophecy about Israel's captivity in Egypt (Exodus 15:13–14). Abraham's grandson, Jacob (Genesis 21:3; 25:26) was also named Israel (Genesis 32:38). He settled in Egypt during a widespread famine (Genesis 47:4–7, 10–11). The prophecy was fulfilled when Egyptian warmth turned into fear, and the Israelites were enslaved (Exodus 1:8–14). After centuries, God sent Moses (Exodus 3:19–20) to lead the people into freedom. Now they make their way to Succoth (Exodus 12:37), having been freed unconditionally (Exodus 12:31–32).This verse repeats that Israel's time in Egypt was 430 years, then uses the phrase "that very day." This is not likely meant to mean that Israel's freedom was granted on the exact same day of the year as Jacob's entry into Egypt. This is probably meant to emphasize that this was when the prophecies were fulfilled. "On that very day" (Exodus 12:51) resembles phrasing used in modern writing to highlight the significance of an event.
"Hosts" is from the Hebrew root word sābā, a term most often applied to military groups (1 Samuel 12:9; Isaiah 1:24; Jeremiah 33:22) and large numbers.