Exodus 4:23

4:23 and I said to you, ‘Let my son go that he may serve ¹  me,’ but since you have refused to let him go, ²  I will surely kill ³  your son, your firstborn!”’”

Exodus 11:5

11:5 and all the firstborn in the land of Egypt will die, from the firstborn son of Pharaoh ⁴  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.

[4:23]  ¹ tn The text uses the imperative, “send out” (שַׁלַּח, shallakh) followed by the imperfect or jussive with the vav (ו) to express purpose.

[4:23]  ² tn The Piel infinitive serves as the direct object of the verb, answering the question of what Pharaoh would refuse to do. The command and refusal to obey are the grounds for the announcement of death for Pharaoh’s son.

[4:23]  ³ tn The construction is very emphatic. The particle הִנֵּה (hinneh) gives it an immediacy and a vividness, as if God is already beginning to act. The participle with this particle has the nuance of an imminent future act, as if God is saying, “I am about to kill.” These words are not repeated until the last plague.

[11:5]  ⁴ 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.