Egypt was one of Israel’s most significant enemies during the lifetime of Moses, but there are clues in the five books of Moses (Genesis–Deuteronomy) that this enemy status would not last forever. As the Israelites were about to enter the Promised Land, God revealed to Moses that the third-generation children of the Egyptians who lived at the time of the exodus would be permitted to join the congregation of His people (Deut. 23:7–8). That generation, presumably, would be far enough removed from the hatred Egypt revealed during the exodus and willing to become servants of the true God — Yahweh, the Lord of Hosts.
Later on, during Isaiah’s lifetime, the Almighty revealed more clearly that Egypt would no longer be Israel’s enemy. Today’s passage anticipates a day when the Egyptians will join God’s people as worshipers of Yahweh, the covenant Lord of Israel. We see this taught in Isaiah 19:18, which says five cities in Egypt will speak the language of Canaan — Hebrew, the tongue of the Israelites who took possession of that land. This is a metaphor explaining how Egypt will become an ally of Israel and adopt Israel’s faith, which was rooted in the fear of the Lord.
Isaiah goes on in verses 19–22 to teach that Egypt will know God not as judge but as redeemer in the last day. Gone will be the pagan altars and false gods, for the Egyptians will be idolaters no longer. During the exodus, the Lord’s glory was manifested when he crushed the Egyptian army in the sea (Ex. 14:17–18). In the eschatological (final or last days) age, His glory will be made known through crushing the hard hearts of Egypt and replacing them with pliable hearts intent on serving Him.
Remarkably, the notoriously cruel empire of Assyria will find peace with Egypt and worship Yahweh as well in that final day (Isa. 19:23–25). Traditionally, Egypt and Assyria were mortal enemies, but the construction of a highway between the two countries signifies a day when they will be friends (v. 23), a day when communication between them will be free and unhindered. Moreover, Assyria will also join with Egypt and the Israelites as a part of the Lord’s holy people (vv. 24–25). This prophecy is being fulfilled as the gospel goes forth and a church of “neither Jew nor Greek” is built into a temple of the living God (Gal. 3:28; 1 Peter 2:4–6).