-Suffering shall lead to repentance. Struck with "terror" and "afraid" (Isaiah 19:17), because of Yahweh's judgments, Egypt shall be converted to Him; nay, even Assyria shall join in serving Him; so that Israel, Assyria, and Egypt, once mutual foes, shall be bound together by the tie of a common faith as one people. So a similar issue from other prophecies (Isaiah 18:7; Isaiah 23:18).
Verse 18. In that day shall five cities in the land of Egypt - i:e., several cities; as in Isaiah 17:6; Isaiah 30:17; Genesis 43:34; Leviticus 26:8. Rather, five definite cities of Lower Egypt (Isaiah 19:11; Isaiah 19:13; Isaiah 30:4), which had close contact with the neighbouring Jewish cities (Maurer): some say, Heliopolis, Leontopolis (else Diospolis), Migdol, Daphne (Tahpanes), and Memphis.
Speak the language of Canaan - i:e., of the Hebrews in Canaan; the language of revelation. A figure. They shall embrace the Jewish religion: so "a pure language" and conversion to God are connected in Zephaniah 3:9. Since also the first confounding and multiplication of languages was the punishment of the making of gods at Babel, other than the One God. Pentecost (Acts 2:4) was the counterpart and antidote of Babel: the separation of nations is not to hinder the unity of faith: the full realization of this is yet future (Zechariah 14:9; John 17:21): 'Multae terricolis linguae, coelestibus una.' One language alone was the vehicle of honouring God in Israelite times. In the coming antitype to the old theocracy, "the multitude which no man can number, of all tongues" shall sing one and the same song of praise for "salvation" to the Lamb (Revelation 7:9). Mark is reported by tradition to have preached the Gospel in Alexandria and Egypt. Then their language became spiritually that "of Canaan," the heavenly inheritance: it was no longer uncircumcised, but pure (Isaiah 6:5).
And swear to the Lord of hosts, This clause agrees with this view - i:e., shall bind themselves to Him by solemn covenant (Isaiah 45:23; Isaiah 65:16; Deuteronomy 6:13).
City of destruction - [ hacherec ]. Onias, who had fled, in disappointment at not getting the high-priesthood, into Egypt, and rose to high rank under Ptolemy Philometer, read 'city of the sun' [ hacherec ] - i:e., On, or Heliopolis: he persuaded Ptolemy Philometer (149 BC) to let him build a temple in the prefecture (nome) of Heliopolis, on the ground that it would induce Jews to reside there, and that the very site was foretold by Isaiah 600 years before. So 16 manuscripts. So Vulgate reads. The Chaldaic reads, 'One of them shall be called The city, the house of the sun which is doomed to be destroyed.' The reading of the Hebrew text is, however, better supported, "city of destruction," referring to Leontopolis, the site of Onias' temple: which casts a reproach on that city because it was about to contain a temple rivalling the only sanctioned temple, that at Jerusalem. Maurer and Gesenius translate, 'city of defense,' or 'deliverance'-namely, Memphis, or some such city, to which God was about to send a "saviour" (Isaiah 19:20), to 'deliver them from their many calamities.'
Verse 19. Altar - not for sacrifice, but as the "pillar" for memorial and worship (Joshua 22:22-26). Isaiah does not contemplate a temple in Egypt: for the only legal temple was at Jerusalem; but, like the patriarchs, they shall have altars in various places.
And a pillar - such as Jacob reared (Genesis 28:18; Genesis 35:14); it was a common practice in Egypt to raise obelisks commemorating divine and great events.
At the border - of Egypt and Judah, to proclaim to both countries the common faith. This passage shows how the Holy Spirit raised Isaiah above a narrow-minded nationality to a charity anticipatory of Gospel catholicity.
Verse 20. And it - the altar and pillar.
For a sign (of the fulfillment of prophecy) - to their contemporaries.
And for a witness - to their descendants.
Cry unto the Lord - no longer to their idols, but to Yahweh. And he shall send them a saviour - probably Alexander the Great (so "a great one"), whom the Egyptians welcomed as a deliverer (Greek, Soter, a title of the Ptolemies) out of the hands of the Persians, who under Cambyses had been their "oppressors." At Alexandria, called from him, the Old Testament was translated into Greek for the Greek-speaking Jews, who in large numbers dwelt in Egypt under the Ptolemies, his successors. Messiah is the Antitype ultimately intended (cf. Acts 2:10, in "Egypt.")
Verse 21. The Egyptians ... shall do ... oblation - unbloody (Hebrew, minchah ).
Verse 22. The Lord shall smite Egypt ... and heal it - as described, Isaiah 19:18-20.
And they shall return (even) to the Lord - for pagan sin and idolatry are an apostasy from primitive truth.