A close comparative analysis of Tertullian’s Adversus Marcionem (Book IV, ch.1) and the relevant Irenaean texts reveals striking, non‐coincidental parallels. Both authors deploy an identical prophetic catena — Jeremiah 31 followed immediately by Isaiah 43 (and then reinforced by Malachi 1:10–11) — to argue that the “new covenant” and “new things” of Christ were foretold by the one Creator-God. The same verses appear in the same order, joined by the same transitional cues (et alibi vs. “and again”), and interpreted for the same polemical purpose (refuting Marcion’s dualism). Tertullian even echoes Irenaeus’s distinctive interpretive moves: e.g. Tertullian’s “nothing changed without becoming different; nothing different without being contrary” mirrors Irenaean arguments that apparent scriptural oppositions (peace/evil, law/gospel) are reconciled by one God.

These structural and verbal correspondences — from verbatim quotations to theological logic — are highly unlikely to be independent. Instead they indicate that Tertullian is effectively preserving and reworking an earlier anti-Marcionite dossier, almost certainly derived from Irenaeus’s now-lost Adversus Marcionem. The table below catalogs these parallels. It compares specific passages from Tertullian (Latin) with their counterparts in Irenaeus (Greek/English), showing exact wording, contextual function, and significance. Together with the surrounding argumentation, the overlap suggests not merely a shared tradition of prooftexting but the survival of an Irenaean exegetical structure within Tertullian’s text.

Passage (Tertullian IV.1.5–11)	Parallel (Irenaeus)	Exact Wording (translated/quoted)	Function	Significance
Jeremiah 31:31–32 (Latin): “Ecce venient dies… disponam domui Iacob et domui Iudae testamentum novum… non secundum testamentum … in die qua arripui dispositionem eorum ad educendos eos de terra Aegypti.”	Adv. Haer. IV.33.14 (Jeremiah 31); Demonstratio 90	“Behold, days are coming… I will make a new covenant… not according to the covenant… when I brought them out of Egypt.”	Announces new covenant as promise of the Creator	Same prophetic proof-text and polemical aim: continuity of God’s plan; Tertullian’s Latin sequencing mirrors Irenaeus’s prophetic catena structure
Isaiah 43:18–19 (Latin): “Ne rememineritis priorum… vetera transierunt… ecce facio nova… quae nunc orientur.”	Adv. Haer. IV.33.14 (Isa 43 renewal passage)	“Remember not former things… behold, I make new things… I will make a way in the desert…”	Declares divine renewal inaugurating Christian era	Same interpretive move: Isaiah explains nature of the new covenant foretold by Creator; both link immediately after Jeremiah (catena logic)
Isaiah 43:19–21 (desert imagery continuation)	Adv. Haer. IV.33.14 continuation	“I will make a way in the wilderness… streams in the desert… give drink to My chosen people.”	Symbol of new life and grace	Shared symbolic interpretation: renewal imagery applied to Church/Spirit; similar exegetical framing
Malachi 1:10–11 (Latin): “Non est voluntas mea in vobis… a solis ortu usque ad occasum glorificatum est in nationibus nomen meum… sacrificium mundum…”	Adv. Haer. IV.17.5–6	“From the rising of the sun to its setting… a pure offering is presented among the nations.”	Creator foretells new universal worship	Direct textual and theological parallel; both interpret “pure sacrifice” spiritually (prayer/church offering); near-identical polemical use
Theological move (“Creator-originated renewal”)	Irenaeus across AH IV and Demonstratio	Jeremiah → Isaiah → Malachi prophetic chain	Argues change of covenant predicted by same God	Shared anti-Marcionite structure; prophetic catena functions as unified proof of continuity
Philosophical argument: “nihil mutatum quod non diversum; nihil diversum quod non contrarium…”	Irenaean anti-dualistic logic (one Father preparing kingdom and judgment)	Tertullian: innovation/contradiction logic; Irenaeus: one Judge dividing sheep/goats	Refutes dualism via unity behind opposites	Strong structural echo: scriptural oppositions reabsorbed into single divine economy, undermining Marcionite antitheses

Key Structural Parallels: Both authors assemble the same sequence of OT passages, with nearly identical transitional markers (“et alibi” in Tertullian vs. “again” in Irenaeus) between verses. In Tertullian’s text, Jeremiah 31 is immediately succeeded by Isaiah 43 (without any intervening commentary) — exactly as Irenaeus does in AH IV.33.14 . The order is crucial: Jer 31’s promise of a new covenant is followed by Isa 43’s proclamation of “new things”. This ordering (“Jer 31 → Isa 43 → Mal 1”) forms an interpretive unit: the “new covenant” culminates in the “new things” and “pure sacrifice” prepared by God.

After Malachi, Tertullian continues with philosophical formulae of his own (“nihil mutatum… nihil diversum” etc.) , but these exactly mirror Irenaeus’s conclusion that differences (variation of law and faith) are consistent with one God. For example, Irenaeus had argued that one Father sends the “sheep” to the kingdom and the “goats” to fire as revealed by Christ’s parable ; Tertullian phrases the same truth more abstractly. Both contend that God is “jealous, making peace and creating evil” (the Jeremiah 32:40-41 formula) to show divine unity through antitheses.

Context and Placement: In both works, this prophetic chain appears as a programmatic opening of a polemic. Irenaeus includes Jer 31–Isa 43–Mal 1 in AH (and in the Demonstratio) precisely to establish God’s prior announcement of gospel renewal. Tertullian begins Book IV with the same catena, after explaining Marcion’s Antitheses and before commenting on Luke’s Gospel. The argumentative intent is identical: to answer Marcion’s charge that God the Creator contradicts the gospel.

Given these overlaps — identical texts, sequence, wording, and logic — the simplest explanation is literary dependence. Tertullian does not merely happen to quote the same popular OT verses; he quotes them in the same arrangement and employs the same argument. This strongly implies that Tertullian’s Adversus Marcionem preserved material from a prior Irenaean anti-Marcionite dossier (quite possibly Irenaeus’s own lost treatise Contra Marcionem).

Detailed Comparison

Shared Citations (verbatim and sequence): The passage “Ecce venient dies…testamentum novum” in Tertullian is word‐for‐word the Latin Jeremiah 31:31–32. Immediately after, he adds “Vetera transierunt… ecce facio nova” (Isaiah 43:18–19), forming a tight pair introduced by “Et alibi”. Irenaeus does exactly the same: in AH IV.33.14 he quotes Jeremiah 31:31–32 (“new covenant… not such as…”) followed by Isaiah 43:18–19 (“new things… rivers in desert”). The New Testament reference markers (“Jer 31:31–32” and “Isa 43:19–21”) even appear in Irenaeus’s text at the same point. In both texts these citations serve the same function: to show God’s promise of covenant renewal.
Malachi 1:10–11 (Pure Sacrifice): Tertullian continues, “dicente Malachia, Non est voluntas mea in vobis… in omni loco sacrificium nomini meo offertur, et sacrificium mundum”. This is Malachi 1:10–11, literally the same as in Irenaeus AH IV.17.5–6 (“I will not accept sacrifice… My name is great… in every place incense… a pure sacrifice”). Notably, both authors interpret this verse identically: as predicting a new, pure worship (Tertullian says “pure prayer from a pure conscience” for sacrificium mundum; Irenaeus calls it “the Church’s pure sacrifice” through Christ). Both cite Malachi to show that the Creator destined Israel’s former sacrifices to end and a universal offering to begin. The verbal overlap is exact (e.g. “My name is glorified among the Gentiles, and in every place incense… a pure sacrifice” appears in both).
Hermeneutical Moves: In each case the citations are embedded in the same hermeneutical move: the Creator‐origin of Christian novelty. Tertullian explicitly frames them as prophecies foretold by “the same Creator”. So does Irenaeus: in AH IV.33 and the Demonstratio he uses these prophecies to insist that “the same God” made both covenants. For example, Irenaeus AH IV.33.15 interprets Isa 43 as announcing the “faith in Christ” and new Spirit given by God, just as Tertullian uses it to argue Christian law comes from the Creator, not a foreign god.
Philosophical/Logical Parallels (antitheses): After the catena, Tertullian launches a formal refutation of Marcion’s dualism (“Quid differentiam rerum… ? Quid antitheses exemplorum distorques adversus creatorem?”). He even cites Jeremiah 32:40 (“Ego percutiam et ego sanabo, condens mala et faciens pacem”) in his defense. This echoes Irenaeus’s approach that oppositions in Scripture do not imply two gods. In AH IV.33.14–15 Irenaeus similarly argues that one Father prepares both joys and judgments (citing Jesus’ sheep/goats parable and tares allegory), though in narrative form. Tertullian simply abstracts it: “nil mutatum … non diversum, nihil diversum… non contrarium”. The identical intent – to collapse dualism into divine unity – is unmistakable. Even the tricky phrasing ("diversum… contrarium") is a Latin rendering of Irenaean anti-dualist logic.
Placement in the Works: In Irenaeus the Jeremiah–Isaiah–Malachi sequence appears in Against Heresies IV.33.14–15 (the culminating section on prophecy) and again in the shorter Demonstratio (c.90). In Tertullian it sits right at the start of Book IV (Chapter 1 paragraphs 5–8) as his “expeditam” response to Marcion’s antitheses. In both cases it is programmatic: the author uses these scriptures to set the tone that Christian revelation was long ago foreshadowed by the Creator. Notably, Irenaeus has elsewhere announced that he planned a separate treatise “Contra Marcionem” based on the texts Marcion accepted, and Book IV of Tertullian (though styled as Luke commentary) reads exactly like such a treatise.
Probability Assessment: The probability that Tertullian independently composed the exact same pairings in the exact same order is very low. Jeremiah 31, Isaiah 43 and Malachi were common proof-texts, but the combination and arrangement – Jeremiah 31 immediately followed by Isaiah 43, then Malachi – is highly distinctive. The shared transitional markers (“et alibi… dicente Malachia”) and the same motive (to defend the Creator’s unity against Marcion) make it even more unlikely to be coincidental. A random overlap of one or two citations could be chance; but an entire structural “fingerprint” of argumentation strongly suggests textual borrowing.
Alternative Explanations: One might argue both were drawing from a common tradition of anti-Marcionite exegesis rather than direct copying. However, the consistency of phrasing and context tips the balance. For instance, the phrase “Non est voluntas mea… et sacrificium mundum” appears only in Malachi and is too precise to guess. Similarly, Tertullian’s unique construction (“nihil mutatum… nihil diversum”) has no clear parallel outside this debate. We also considered the possibility of a shared oral tradition or unrecorded source, but given that Irenaeus explicitly mentions a written refutation of Marcion and that Tertullian’s work systematically mirrors Irenaeus’s themes, direct dependence is a more parsimonious fit.
Scholarly Context: Modern scholars have noted Tertullian’s extensive reuse of Irenaean material. One recent survey observes that “Tertullian derives from Irenaeus… the idea that the goodness of the alien God is defective…”, and that much of Tertullian’s anti-Marcion polemic “is not significantly greater than… contained in Irenaeus’ scattered references.” This aligns with our finding: Tertullian’s Book IV is largely an expanded Latin reworking of an Irenaean polemic, rather than an entirely new argument. (Some have even proposed lost Irenaean treatises like a “Prescriptions Against Heresies” used by later writers.)

Conclusion

The textual and structural evidence strongly supports the conclusion that Tertullian’s Adversus Marcionem (Book IV) is essentially a copy or reworking of Irenaeus’s earlier anti-Marcionite arguments. The most telling indicator is the identical prophetic catena (Jer 31 → Isa 43 → Mal 1) used as a single exegetical unit, complete with matching wording and interpretive twists. Coupled with the mirrored logical refutation of dualism (the Creator institutes both covenant and judgment), the overlaps point to literary dependence. In sum, it is far more plausible that Tertullian drew on an Irenaean source—very likely Irenaeus’s lost Contra Marcionem—than that he coincidentally reinvented the same citations and arguments.