In Ex 12:38, the word translated "mixed" is עֵרֶב (ereb) which occurs about 15 times in the OT. It is used in several ways:
- "mixed" group of people or "foreigners" who have not become Israelites, Ex 12:38, Neh 13:3, Jer 25:20, 24, 50:37.
- "woof" as in warp and woof of woven cloth, Lev 13:48-59
- "Arabia" (the country), or "mixed peoples", Eze 30:5.
It appears that following the series of miracles that God performed in Egypt, many locals, Egyptians and others, decided to leave with the Israelites and joint them in their trek to Worship the God of heaven and earth. This had been going on for several generation previously.
When Jacob entered Egypt, his family numbered 75 people (Acts 7:14, Ex 1:5). Some of these were not direct descendants of Abraham such as the wives of the 12 patriarchs, notably Joseph’s own wife. 215 years and four generations later at the exodus, Israel’s army had over 600,000 men excluding women and children, (Ex 12:37, Num 1:46, etc) suggesting a total population of several million people, requiring many additions. This included a significant mixed multitude (Ex 12:38) showing that Israel obviously consisted of many non-biological Jews had joined. (Note that it is biologically impossible for Israelite numbers to have grown from 75 to several million biologically without many outside additions.)
Indeed, the Old Testament contains many examples of foreigners becoming part of Israel, indicating that the Israelite Covenant was open to all and was never exclusive. For example:
- Abraham’s own household must have consisted of perhaps 2000 people just to be able to raise an army of 318 men to liberate Lot, Gen 14:14. Indeed, Abraham’s chief servant (from Damascus) was clearly a believer and very devout as shown in Gen 24.
- Moses married a Midianite (Ex 2:16-21).
- Caleb, who represented and led the tribe of Judah was a Kennizite (Num 32:12).
- Rahab was a Canaanite (Josh 2:1, 2, Matt 1:5)
- Ruth was Moabite (Ruth 1:4 16, 17, Matt 1:5) – these last two make King David descended from foreigners (Ruth 4:13-16).
- Uriah was a Hittite (2 Sam 11:3)
- King David’s elite personal regiment was Gittite, Philistines (1 Chron 18:17)
- The Rechabites were Kenites (Jer 35:1-19)
- Many other foreigners lived in Israel (1 Chron 22:2, 17, 2 Chron 30:25)
- In Esther’s time “many of the people of the land became Jews” (Esther 8:17, 9:27)
- Even in NT times, many Jewish synagogues were attended by godly gentiles converted to Judaism (Acts 13:16, 26, 16:14, 17:17)
- Many Jewish proselytes came to worship in Jerusalem (John 20:20, Acts 2:9-11)
- Jesus quotes Isa 56:7, “My house shall be a house of prayer for all nations”, Mark 11:17.
- Further, biological Israelites could opt out of the covenant and be cut-off (Ex 30:33, 38, 31:14, Lev 7:20, 21, 25, 27).
Thus, it is abundantly clear that membership of Israel was always open to all and voluntary. See also “Pagan Salvation” for the logical extension of this idea. The distinction between a biological Jew/Israelite and a convert becomes extremely blurred if meaningful at all.
Thus, the Mixed multitude that left Egypt with Israel consisted of those who had been impressed with God's power and the religion of the Israelites and wished to leave Egypt behind.