C. F. Keil and Franz Delitzsch on Isaiah 19:23

Isa 19:23

Asshur, as we already know from Isa 18:1-7, is equally humbled; so that now the two great powers, which have hitherto only met as enemies, meet in the worship of Jehovah, which unites them together. “In that day a road will run from Egypt to Asshur, and Asshur comes into Egypt, and Egypt to Asshur; and Egypt worships (Jehovah)with Asshur.” את is not a sign of the accusative, for there can be no longer any idea of the subjection of Egypt to Asshur: on the contrary, it is a preposition indicating fellowship; and עבדוּ is used in the sense of worship, as in Isa 19:21. Friendly intercourse is established between Egypt and Assyria by the fact that both nations are now converted to Jehovah. The road of communication runs through Canaan.