Albert Barnes Commentary Exodus 12:38

"And a mixed multitude went up also with them; and flocks, and herds, even very much cattle." — Exodus 12:38 (ASV)

A mixed multitude - Probably remains of the old Semitic population, whether first brought into the district by the Hyksos or not is uncertain. As natural objects of suspicion and dislike to the Egyptians who had lately become masters of the country, they would be anxious to escape, all the more after the calamities which preceded the Exodus.

Very much cattle - This is an important fact, both as showing that the oppression of the Israelites had not extended to confiscation of their property, and as bearing upon the question of their maintenance in the Wilderness.