The ten plagues served as an indictment against the wickedness of the Egyptian people (and its Pharaoh), as well as a pervasive attack against the pagan, moral, and economic system of the nation (cf. Ex. 12.12; Num. 33.4).
The God of Israel alone is the God of the Nile river (Ex. 7.14ff) — not Khnum or Sothis; Jehovah alone rules the harvest and the livestock (Ex. 8.1f; 16f; 20f; 9.1f; 9.8f; 10.1f) — not Heket, Apis, or Osiris; he alone governs the earth, sky, and stars (9.13ff; 10.21f) — not Ra.
The Egyptians even worshipped the Pharaoh himself, including his firstborn son, as if they were gods on earth. Moses' actions to free his people from their grasp proved that a mere servant of the Lord God wielded greater authority than an alleged family of gods on earth.
As Jesus pronounced years later, the God of the Bible is "the only true God" (John 17.3). The plagues were "his signs" and "wonders" (Psalm 78.43), which he accomplished through the outstretched hands of his servants, Moses and Aaron (Ex. 7.19; 9.22).
By them, many came to know the identity of the supreme ruler of the universe — in contradistinction to the false gods of Egyptian lore (cf. Ex. 18.10-11).
The tenth plague in particular took the lives of every firstborn in Egypt, whose house was not covered with blood on the lintel and the two doorposts (cf. Ex. 12.23).
But there is some confusion as to the identity of these "firstborn." Were they the firstborn child (the first child to be born from the mother, whether male or female)? Or, males only? What about houses with all girls?
Firstborn Males
Although the New International Version suggests that "every firstborn son in Egypt will die" (Ex. 11.5), it is the only version to do so. Nonetheless, that is the significance of the passage.
First, in oriental culture, the term, firstborn, alluded to the first male to open the womb. The eldest son
"had special privileges within the family. He received the special family blessing, which meant spiritual and social leadership and a double portion of the father's possessions — or twice what all the other sons received (Deut. 21.17)" (Vine, 83).
Strong defines the Hebrew term as the
"first male offspring (human or animal), the oldest son, with associative meanings of honor, status, prominence, and privilege of inheritance to the firstborn" (1480).
The loss of these firstborn males doubtless devastated the Egyptian social structure.
By contrast, the nation of Israel was God's firstborn — receiver of the blessing of prominence and spiritual inheritance among the nations. Hence, Pharaoh's cruel oppression and slavery of God's firstborn (Israel) became the catalyst for the final plague.
God told Pharaoh:
"let my son go that he may serve me. But if you refuse to let him go, indeed I will kill your son, your firstborn" (Ex. 4.23).
If he had listened to the Lord, the tenth plague would never have occurred. In the end, however, Pharaoh would ultimately be responsible for the death of his own firstborn son, as well as the death of all the Egyptian heirs (firstborn males).
Second, Psalm 78.51 and 105.36 describe the firstborn of Egypt as "the first of their strength." This expression applied only to the male heirs in the family (cf. Deut. 21.15-17). Hence, females were not counted among those who were slain in the tenth plague.
Third, the law of redemption, which involved only the firstborn males (Ex. 13.12-15; Lk. 2.23), functioned as a memorial of the tenth plague (Ex. 13.11-16; Num. 8.13-19). As God required the lives of every firstborn male in Egypt, of man and beast, so God requires the lives of "all the firstborn in Israel, both man and beast" (Num. 3.13). Just as he killed the firstborn males of Egypt, he kills the firstborn males of clean animals in Israel with priestly sacrifices (Num. 18.15-18). And just as he bought back (redeemed) his own firstborn son (Israel) from Egyptian slavery (cf. Ex. 6.6-7; Ps. 78.35), he, in like manner, redeems Israel's firstborn males, allowing them to be passed-over (and survive), when their fathers pay the redemption price to the priest (five shekels, Num. 18.16).
This taught Israel that there is a penalty for sin (viz., death, Rm. 6.23), and that there is a reward for righteousness (viz., life, Rm. 6.22-23).
Fourth, Amos 4.10 involves a condemnation of Israel. God said, "I sent you a plague after the manner of Egypt, your young men I killed with the sword along with your captive horses…" In all likelihood this means: just as he killed the males of Egypt, both of men and beasts, so he also killed Israel's males (man and beast), in retribution for their sins.
He killed the Egyptians via the angel of death; the Israelites (of Amos' day), with the sword of war. It was a "plague" in the sense of a grossly calamitous occurrence. Hence, it follows that males were victims of the tenth plague, not females.
Peripheral Points
The sacred record indicates that "there was not a house where there was not one dead" (Ex. 12.30). Since that is so, either of the following must be true:
(1) The expression is figurative in scope — a hyperbole — emphasizing the pervasive nature of the deaths. After the tenth plague occurred, "there was a great cry in Egypt" (Ex. 12.30), causing the Egyptians to urge "the people, that they might send them out of the land in haste. For they said, 'We shall all be dead' (Ex. 12.33). The phrase, there was not a house..., may be another way of saying, the deceased were many and widespread, affecting everyone and everything.
(2) The expression is literal. Every Egyptian domicile inhabited a male firstborn. There were no all-female dwellings. This is possible, albeit rather implausible.
(3) The term, house, more likely refers to the family. Every family suffered the loss of some male heir (firstborn), including a son, a brother, a father, an uncle, or grandfather.
Conclusion
We must never forget, in the midst of all the Lord's supernal, Christian mercies, that he is also a just God — both good and severe (cf. Rm. 11.22) — and that there would be no justice without punishment for evil (for a study of the justice of God in punishing those who do evil, see: "The Cup of Iniquity") .
Those who are willing and obedient shall inherit eternal life as his spiritual firstborn, whether male or female (cf. Gal. 3.28-29; 4.7; 1 Pt. 1.3-5; Heb. 12.23); those who refuse and rebel shall meet with death and judgment in the next life (cf. Mt. 25.46; 2 Thess. 1.6-9; Heb. 10.26-31).
In the words of G. A. Chadwick, in commentating on the main lesson of the final Egyptian plague:
"What God requires must ultimately be done; and human resistance, however stubborn and protracted, will only make the result more painful and more signal at the last" (Nicoll, 170).
Nicoll, W. Robertson. The Expositor's Bible: Volume 1, Genesis-Ruth. New York: George H. Doran Company, n.d.
Strong, James. The Strongest Strong's: Exhaustive Concordance of the Bible. Grand Rapids, MI: Zondervan, 2001.
Vine, W.E. Vine’s Complete Expository Dictionary of Old and New Testament Words. Nashville, TN: Thomas Nelson, Inc., 1985.