Biblical Context:
The announcement of the final plague is a pivotal moment in the narrative of the Exodus, where God demonstrates His supreme power over Egypt and its deities. This event is recorded in the Book of Exodus, specifically in Exodus 11. The final plague, the death of the firstborn, serves as the climactic act of divine judgment against Pharaoh and the Egyptians, compelling them to release the Israelites from bondage.

Scriptural Account:
In Exodus 11, the LORD speaks to Moses, revealing the impending judgment that will lead to the liberation of the Israelites. The LORD declares, "I will bring one more plague on Pharaoh and on Egypt. After that, he will let you go from here, and when he does, he will drive you out completely" (Exodus 11:1). This final plague is distinct in its severity and its direct impact on every Egyptian household, from the palace of Pharaoh to the humblest of servants.

Divine Judgment:
The final plague is characterized by the death of the firstborn in every Egyptian family, a direct challenge to the Egyptian belief system and a demonstration of the LORD's sovereignty. The LORD instructs Moses to warn Pharaoh of the impending disaster, saying, "About midnight I will go throughout Egypt, and every firstborn son in Egypt will die, from the firstborn son of Pharaoh, who sits on the throne, to the firstborn son of the female slave, who is at her hand mill, and all the firstborn of the cattle as well" (Exodus 11:4-5).

Significance for Israel:
For the Israelites, the announcement of the final plague is a moment of divine intervention and deliverance. It marks the beginning of their journey to freedom and the fulfillment of God's promises to their forefathers. The LORD makes a distinction between the Egyptians and the Israelites, ensuring that the latter are spared from the devastation. This distinction underscores the covenant relationship between God and His chosen people.

Pharaoh's Hardened Heart:
Despite the severity of the previous plagues, Pharaoh's heart remains hardened. The announcement of the final plague is a testament to the LORD's patience and justice. It highlights the futility of resisting God's will and the inevitable triumph of His purposes. The LORD tells Moses, "Pharaoh will not listen to you, so that My wonders may be multiplied in the land of Egypt" (Exodus 11:9).

Theological Implications:
The announcement of the final plague is rich with theological significance. It reveals God's justice, mercy, and faithfulness. The event foreshadows the ultimate deliverance through Christ, the Lamb of God, whose sacrifice brings salvation to all who believe. The Passover, instituted immediately following the announcement, becomes a lasting ordinance for the Israelites, symbolizing redemption and pointing to the future atonement through Jesus Christ.

Cultural and Historical Context:
In the ancient Near Eastern context, the death of the firstborn was a devastating blow, as the firstborn held a place of prominence and inheritance. The final plague not only dismantles the Egyptian social and religious order but also serves as a powerful demonstration of the LORD's supremacy over all gods and nations.

Conclusion:
The announcement of the final plague is a defining moment in the biblical narrative, showcasing God's power, justice, and commitment to His people. It sets the stage for the Exodus, a foundational event in Israel's history and a profound testament to God's redemptive plan for humanity.