18 In that day shall there be five cities in the land of Egypt speaking the language of Canaan, and swearing by Jehovah of hosts: one shall be called, The city of Heres. 19 In that day shall there be an altar to Jehovah in the midst of the land of Egypt, and a pillar at the border thereof to Jehovah: 20 and it shall be for a sign and for a witness to Jehovah of hosts in the land of Egypt; for they shall cry unto Jehovah because of the oppressors, and he will send them a saviour and defender, who shall deliver them. 21 And Jehovah shall be known to the Egyptians, and the Egyptians shall know Jehovah in that day, and shall serve with sacrifice and oblation; and they shall vow a vow unto Jehovah, and perform it. 22 And Jehovah will smite Egypt; he will smite and heal: and they shall return to Jehovah, and he will be entreated of them, and will heal them.
Matthew Henry's Commentary on Isaiah 19:18-22
Commentary on Isaiah 19:18-25
(Read Isaiah 19:18-25)
The words, "In that day," do not always refer to the passage just before. At a time which was to come, the Egyptians shall speak the holy language, the Scripture language; not only understand it, but use it. Converting grace, by changing the heart, changes the language; for out of the abundance of the heart the mouth speaks. So many Jews shall come to Egypt, that they shall soon fill five cities. Where the sun was worshipped, a place infamous for idolatry, even there shall be a wonderful reformation. Christ, the great Altar, who sanctifies every gift, shall be owned, and the gospel sacrifices of prayer and praise shall be offered up. Let the broken-hearted and afflicted, whom the Lord has wounded, and thus taught to return to, and call upon him, take courage; for He will heal their souls, and turn their sorrowing supplications into joyful praises. The Gentile nations shall not only unite with each other in the gospel fold under Christ, the great Shepherd, but they shall all be united with the Jews. They shall be owned together by him; they shall all share in one and the same blessing. Meeting at the same throne of grace, and serving with each other in the same business of religion, should end all disputes, and unite the hearts of believers to each other in holy love.