11:5 and all the firstborn in the land of Egypt will die, from the firstborn son of Pharaoh 1 who sits on his throne, to the firstborn son of the slave girl who is at her hand mill, and all the firstborn of the cattle.
12:29 2 It happened 3 at midnight – the Lord attacked all the firstborn in the land of Egypt, from the firstborn of Pharaoh who sat on his throne to the firstborn of the captive who was in the prison, and all the firstborn of the cattle.
1 sn The firstborn in Egyptian and Israelite cultures was significant, but the firstborn of Pharaoh was most important. Pharaoh was considered a god, the son of Re, the sun god, for the specific purpose of ruling over Re’s chief concern, the land of Egypt. For the purpose of re-creation, the supreme god assumed the form of the living king and gave seed which was to become the next king and the next “son of Re.” Moreover, the Pharaoh was the incarnation of the god Horus, a falcon god whose province was the heavens. Horus represented the living king who succeeded the dead king Osiris. Every living king was Horus, every dead king Osiris (see J. A. Wilson, “Egypt,” Before Philosophy, 83-84). To strike any firstborn was to destroy the heir, who embodied the hopes and aspirations of the Egyptians, but to strike the firstborn son of Pharaoh was to destroy this cardinal doctrine of the divine kingship of Egypt. Such a blow would be enough for Pharaoh, for then he would drive the Israelites out.
2 sn The next section records the deliverance of Israel from Egypt, and so becomes the turning point of the book. Verses 28 and 29 could be included in the exposition of the previous section as the culmination of that part. The message might highlight God’s requirement for deliverance from bondage through the application of the blood of the sacrifice, God’s instruction for the memorial of deliverance through the purging of corruption, and the compliance of those who believed the message. But these verses also form the beginning of this next section (and so could be used transitionally). This unit includes the judgment on Egypt (29-30), the exodus from Egypt (31-39) and the historical summation and report (40-42).
3 tn The verse begins with the temporal indicator וַיְהִי (vayÿhi), often translated “and it came to pass.” Here it could be left untranslated: “In the middle of the night Yahweh attacked.” The word order of the next and main clause furthers the emphasis by means of the vav disjunctive on the divine name preceding the verb. The combination of these initial and disjunctive elements helps to convey the suddenness of the attack, while its thoroughness is stressed by the repetition of “firstborn” in the rest of the verse, the merism (“from the firstborn of Pharaoh…to the firstborn of the captive”), and the mention of cattle.