Discovery BoxExodus 12:40-42 
Context12:40 Now the length of time the Israelites lived in Egypt was 430 years. 1 12:41 At the end of the 430 years, on the very day, all the regiments 2 of the Lord went out of the land of Egypt. 12:42 It was a night of vigil for the Lord to bring them out from the land of Egypt, 3 and so 4 on this night all Israel is to keep the vigil 5 to the Lord for generations to come.
1 sn Here as well some scholars work with the number 430 to try to reduce the stay in Egypt for the bondage. Some argue that if the number included the time in Canaan, that would reduce the bondage by half. S. R. Driver (Exodus, 102) notes that P thought Moses was the fourth generation from Jacob (6:16-27), if those genealogies are not selective. Exodus 6 has Levi – Kohath – Amram – Moses. This would require a period of about 100 years, and that is unusual. There is evidence, however, that the list is selective. In 1 Chr 2:3-20 the text has Bezalel (see Exod 31:2-5) a contemporary of Moses and yet the seventh from Judah. Elishama, a leader of the Ephraimites (Num 10:22), was in the ninth generation from Jacob (1 Chr 7:22-26). Joshua, Moses’ assistant, was the eleventh from Jacob (1 Chr 7:27). So the “four generations” leading up to Moses are not necessarily complete. With regard to Exod 6, K. A. Kitchen has argued that the four names do not indicate successive generations, but tribe (Levi), clan (Kohath), family (Amram), and individual (Moses; K. A. Kitchen, Ancient Orient and Old Testament, 54-55). For a detailed discussion of the length of the sojourn, see E. H. Merrill, A Kingdom of Priests, 75-79.
2 sn This military term is used elsewhere in Exodus (e.g., 6:26; 7:4; 12:17, 50), but here the Israelites are called “the regiments of the Lord.”
3 tn There is some ambiguity in לֵיל שִׁמֻּרִים הוּא לַיהוָה (lel shimmurim hu’ la’adonay [layhveh]). It is likely that this first clause means that Yahweh was on watch for Israel to bring them out, as the next clause says. He was protecting his people (S. R. Driver, Exodus, 102). Then, the night of vigil will be transferred to Israel, who now must keep it “to” him.
4 tn “and so” has been supplied.
5 tn Heb “this night is for Yahweh a vigil for all Israelites for their generations.”
