Catholic Commentary
'In That Day': Egypt's Conversion and Worship of Yahweh
18In that day, there will be five cities in the land of Egypt that speak the language of Canaan, and swear to Yahweh of Armies. One will be called “The city of destruction.”19In that day, there will be an altar to Yahweh in the middle of the land of Egypt, and a pillar to Yahweh at its border.20It will be for a sign and for a witness to Yahweh of Armies in the land of Egypt; for they will cry to Yahweh because of oppressors, and he will send them a savior and a defender, and he will deliver them.21Yahweh will be known to Egypt, and the Egyptians will know Yahweh in that day. Yes, they will worship with sacrifice and offering, and will vow a vow to Yahweh, and will perform it.22Yahweh will strike Egypt, striking and healing. They will return to Yahweh, and he will be entreated by them, and will heal them.
God's judgment of Egypt is not final—it is the prelude to the deepest conversion, where the ancient enemy becomes a worshiper in Yahweh's house, forever undoing the logic of the Exodus.
In a remarkable reversal of the Exodus narrative, Isaiah envisions the ancient enemy Egypt turning to Yahweh — building altars, offering sacrifices, crying out for a savior, and being healed of the very wounds God inflicts. These verses form one of the most breathtaking universalist oracles in all of the Old Testament, anticipating the Catholic doctrine that salvation is offered to all peoples, and that the Church's mission reaches to the ends of the earth.
Verse 18 — Five Cities and the Language of Canaan The number five is likely symbolic of completeness within a portion rather than the whole (compare the five books of the Torah, the five-fold division of the Psalter). That these Egyptian cities will "speak the language of Canaan" — that is, Hebrew, the sacred tongue of God's covenant people — signals a radical cultural and spiritual conversion. Language in the ancient world was inseparable from identity and worship; to adopt the language of Israel was to adopt the God of Israel. The mysterious name "City of Destruction" (Hebrew heres, though some manuscripts read heres meaning "sun," likely a pointed reference to the sun-worship center of Heliopolis/On) signals that even the heartlands of pagan solar religion will be overturned. The ambiguity in the Hebrew is itself suggestive: the city whose name once meant destruction (of pagan worship) will become a place of covenant fidelity.
Verse 19 — Altar and Pillar An altar in the middle of Egypt and a pillar at its border evoke the structure of sacred space. The altar in the center recalls the Temple in Jerusalem — the heart of covenant worship — now transplanted into Egypt's very interior. The pillar (massebah) at the border functions as a boundary marker, a memorial stone, recalling Jacob's pillar at Bethel (Gen 28:18) and the stones of witness throughout the Pentateuch. Together, altar and pillar signify that all of Egypt — from center to frontier — is now consecrated to Yahweh. The Church Fathers (e.g., Eusebius of Caesarea, Demonstratio Evangelica IX) read this altar as a figure of the Eucharistic altar spread among the Gentile nations through the Church's mission.
Verse 20 — Sign, Witness, and Savior The language of "sign and witness" (ot and ed) is deeply covenantal. Signs throughout Scripture mark God's saving presence (the rainbow, circumcision, the Passover). The word for "savior" here (moshia) is the same root as Yeshua — Jesus. Catholic tradition reads this verse as a prophetic silhouette of Christ: when Egypt (the nations) cries out under oppression (sin and death), God sends not an angel but a Savior who defends and delivers. The Catechism teaches that "the Word of God, through whom all things were made, was himself made flesh so that as perfect man he might save all men" (CCC 315). The sequence — cry, send, deliver — mirrors the structure of the Exodus itself, now universalized.
Verse 21 — Mutual Knowledge and True Worship "Yahweh will be known to Egypt, and Egypt will know Yahweh" — this double declaration of mutual knowing uses the Hebrew , a word that in Scripture connotes not merely intellectual acquaintance but intimate, covenantal relationship (cf. Jer 31:34; Hos 2:20). The triad of "sacrifice and offering… vow… and perform it" describes the full cycle of authentic worship: external act, interior commitment, and faithful follow-through. This is not syncretism but full conversion — Egypt worships not a re-named Egyptian deity but , the God of Abraham, Isaac, and Jacob.
Catholic tradition finds in these verses a prophetic foreshadowing of the universal scope of the Church. The Second Vatican Council, in Lumen Gentium §16, teaches that those who "through no fault of their own do not know the Gospel of Christ or His Church, but who nevertheless seek God with a sincere heart… may achieve eternal salvation." Isaiah 19 stands as the scriptural anchor for this conviction: God's saving will is not bounded by ethnic or national lines.
St. Cyril of Alexandria (5th century) wrote extensively on this passage in his Commentary on Isaiah, identifying the "altar in the middle of Egypt" explicitly with the Eucharist celebrated in Gentile lands — a stunning patristic endorsement of the Church's sacramental mission to the nations. Origen likewise saw the five cities as the multitude of the Gentile world receiving the Gospel.
The striking-and-healing dynamic of verse 22 is a key locus for the Catholic theology of medicinal punishment. The Catechism teaches that "God's chastisements… are medicinal; they aim at the correction of the sinner" (cf. CCC 1459, 1473). This stands against any purely retributive theology of suffering: affliction in God's hands is always ordered toward conversion and communion. Pope Benedict XVI, in Spe Salvi §47, drew on this tradition in describing purgation as God's burning, transformative love — severe but wholly aimed at healing.
Finally, the oracle's culmination — mutual knowledge between God and Egypt — anticipates what the Church calls the sensus fidei finding its fullness: the whole human family drawn into the covenant knowledge (gnosis) that is eternal life (cf. John 17:3).
These verses challenge the Catholic reader to examine the boundaries she unconsciously draws around God's mercy. Egypt was not merely a foreign nation to ancient Israel — it was the archetypal oppressor, the house of slavery, the land of idols and Pharaonic pride. Yet God's plan encompasses even Egypt's conversion and healing.
For contemporary Catholics, this passage is a corrective against any tendency to treat the Church as a fortress for the already-saved rather than a field hospital (Pope Francis, Evangelii Gaudium §47) for those still far off. The image of Egypt crying out and God sending a savior maps directly onto every person who has ever reached the end of their resources and called out — however haltingly, however imperfectly — to the God they barely know.
Practically: when you encounter someone from a background, culture, or religion that seems alien to the Gospel, Isaiah 19 invites you to see them as Egypt — not doomed, but perhaps on the eve of their altar and their cry. Intercede for them. The oracle also speaks to anyone enduring God's "striking": suffering is not the sign of abandonment, but potentially the prelude to the deepest healing.
Verse 22 — Striking and Healing The phrase "striking and healing" (nagof ve-rafo) resonates with Deuteronomy 32:39 ("I wound and I heal") and with the theology of divine chastisement throughout the prophets. God's judgment is never merely punitive but medicinal — paideutic (educative), in the patristic term. St. Jerome and St. Cyril of Alexandria both noted this verse as proof that divine discipline is ordered entirely toward restoration. The final movement — "they will return… he will be entreated… he will heal" — is a perfect encapsulation of the structure of repentance and reconciliation, which the Catholic tradition has always identified as the inner logic of the sacrament of Penance.