Catholic Commentary
Solemn Warning Against Altering the Prophecy
18I testify to everyone who hears the words of the prophecy of this book: if anyone adds to them, God will add to him the plagues which are written in this book.19If anyone takes away from the words of the book of this prophecy, God will take away his part from the tree of life, and out of the holy city, which are written in this book.
Revelation 22:18–19 contains Christ's formal warning against adding to or subtracting from the prophecy of Revelation. Those who alter the text face divine judgment—either the plagues described in the book or exclusion from eternal life—with the punishments symmetrically mirroring the violations themselves.
Christ seals Scripture shut with a covenant curse: tamper with His word — add or subtract — and you forfeit the tree of life itself.
The passage also engages the theme of integrity — the wholeness of divine revelation. To add is to say God did not speak fully; to subtract is to say God spoke too harshly or too strangely. Both gestures are acts of disobedience masquerading as reverence. The Church Fathers recognized that heretics typically did both simultaneously, adding their own systems while excising the inconvenient witness of the apostolic deposit.
Catholic tradition brings extraordinary precision to these verses because they stand at the intersection of two of its most foundational doctrines: the canon of Scripture and the integrity of Divine Revelation.
The Council of Trent (Session IV, 1546), responding to Protestant selective use of the biblical canon, solemnly defined the full list of sacred books and declared that the Church receives them "with equal piety and reverence" (pari pietatis affectu). The Tridentine Fathers were acting — consciously or not — in the spirit of Revelation 22:19: to excise books from the canon (as Reformers did with the deuterocanonicals) was precisely the kind of subtraction this verse forbids. St. Robert Bellarmine explicitly invoked the logic of this passage in his defense of the full canon.
Dei Verbum §9–10 (Vatican II) teaches that Scripture, Tradition, and the Magisterium are so interrelated that none can stand without the others. Revelation 22:18–19 supports this architecturally: the "prophecy of this book" is not entrusted to private interpreters but to the Church as a living community of reception, transmission, and interpretation. The Catechism (§113) teaches that Scripture must be read "within the living Tradition of the whole Church" — a principle that stands precisely as a safeguard against unauthorized addition or subtraction.
St. Irenaeus of Lyons (Adversus Haereses I.3) saw the Gnostic heretics as the first great fulfillment of this warning, accusing them of both adding apocryphal texts and excising apostolic ones. For Irenaeus, the integrity of the apostolic deposit was inseparable from salvation itself — a reading perfectly consonant with these verses' linkage of textual integrity to one's standing before the tree of life.
Contemporary Catholics encounter the temptation described in these verses not primarily in the form of manuscript forgery but in subtler, more culturally pervasive ways. The pressure to "add" to Scripture manifests when private revelation, ideological frameworks, or therapeutic spiritualities are treated as correctives or supplements to the apostolic deposit — when something beyond the Gospel is made necessary for salvation or wholeness. The pressure to "subtract" manifests when inconvenient teachings (on judgment, on sexual ethics, on hell) are quietly set aside as embarrassing, culturally dated, or too severe for modern sensibilities.
Practically, these verses call every Catholic to a renewed reverence for the received text of Scripture and for the Church's authoritative interpretation of it. When reading the Bible, the temptation to hear only what is comfortable and to skim past what is demanding is itself a form of subtraction. Lectio divina practiced with the full text — including its warnings, its apocalyptic imagery, its hard edges — is an act of fidelity to the injunction of these closing verses. These are not merely a copyist's rubric; they are Christ's final call to receive Him wholly, on His terms.
Commentary
Revelation 22:18 — "I testify to everyone who hears the words of the prophecy of this book"
The Greek verb martyrō ("I testify") is the language of a formal witness in a legal proceeding. Its speaker is deliberately ambiguous — it could be Christ, the angel, or John acting as prophetic mouthpiece — but the Catholic tradition, drawing on the broader structure of the Apocalypse, understands the ultimate speaker to be the glorified Christ Himself, whose voice has framed this entire revelation (cf. Rev 1:1; 22:16). The phrase "everyone who hears" recalls the Apocalypse's liturgical setting: these words were proclaimed aloud in early Christian assemblies (cf. Rev 1:3), and the warning therefore addresses every hearer in every age, not merely a first-century copyist or scribe.
The conditional curse — "if anyone adds to them, God will add to him the plagues which are written in this book" — employs a sharp lex talionis symmetry: the punishment mirrors the crime. To "add" to the prophecy is to distort the shape of divine truth, and the consequence is not simply poetic justice but a genuine theological claim: one who deforms revelation becomes subject to the full weight of divine judgment catalogued within it — the bowls, the trumpets, the lake of fire.
Revelation 22:19 — "If anyone takes away from the words of the book of this prophecy"
The parallel curse for subtraction is equally severe and equally symmetrical: God will "take away his part from the tree of life and from the holy city." The phrase "tree of life" (xylon tēs zōēs) is a deliberate inclusio with Revelation 22:2 and 22:14, where access to the tree is the inheritance of the blessed. To lose one's "part" (meros) in the tree is to be disinherited from eschatological life — to be among those outside the holy city (Rev 22:15) rather than within it. The word meros also echoes the "share" (meros) in the lake of fire assigned to the wicked (Rev 21:8), sharpening the contrast.
Literal and Spiritual Senses Together
At the literal level, the warning addressed the practical realities of scribal transmission in antiquity, where texts were habitually expanded or compressed. The Apocalypse, deeply controversial in some early communities, needed protection against both enthusiastic interpolation and fearful excision. Yet the spiritual sense reaches far beyond manuscript copying. In the typological reading, these verses complete the great arc of Scripture: just as Moses commanded Israel not to add to or take from the Torah (Deut 4:2; 12:32), so now the New Moses — Christ — pronounces a parallel command over the New Covenant's final and complete revelation. The canonical "seal" enacted here is christological in origin and eschatological in scope.