The answer
It is both literal and metaphorical. Highway means free communication. Literally, under the latter kings of Persia, and under Alexander, Egypt, Judea, and Assyria lived peaceably under the same government, and were on such friendly terms that there was a regular, uninterrupted intercourse between them.Metaphorically, all these countries shall be converted to the Lord. The Assyrians shall become the people of God with the Egyptians. The Egyptians shall serve (shall worship the true God) with the Assyrians; and therefore the Assyrians shall come into Egypt and the Egyptians into Assyria. It becomes those who have communion with the same God, through the same Mediator, to keep up an amicable correspondence with one another. Egypt and Assyria represent all the Gentiles who will believe in the Lord Jesus.
Answered by His Eminence Metropolitan Youssef (opens in a new tab)