In that day shall there be a highway out of Egypt to Assyria, and the Assyrian shall come into Egypt, and the Egyptian into Assyria, and the Egyptians shall serve with the Assyrians.
Highway out of Egypt to Assyria - free communication, resting on the highest basis, the common faith of both (Isaiah 19:18; Isaiah 11:16). Assyria and Egypt were joined under Alexander as parts of his empire: Jews and proselytes from both met at the feasts of Jerusalem. A type of Gospel times to come.
The Egyptians shall serve with the Assyrians - serve Yahweh with the Assyrians. So "serve" is used absolutely (Job 36:11).