Adversus Marcionem IV.1.5 and Irenaeus

	Tertullian — Adversus Marcionem IV.1.5–6	Irenaeus — Demonstratio Apostolica 87
Isaiah Citation (variant form)	Hic erit et sermo, de quo idem Esaias: Quoniam decisum sermonem faciet dominus in terra.	“A word brief and short in righteousness; for a short word will God make in the whole world.” (Isa 10:23 variant)
Key Terminology	decisum sermonem (“a cut/abridged word”)	“short word,” “brief word”
Underlying Scriptural Basis	Isaiah 10:22–23 (LXX tradition: λόγον συντετμημένον / shortened word)	Same Isaianic tradition emphasizing brevity/abridgement
Immediate Interpretation	New covenant is compendiated: Compendiatum est enim novum testamentum — reduced, streamlined	Salvation comes through brevity of faith and love, not lengthy legal discourse
Law vs. New Economy	New testament freed from “laciniosis oneribus legis” (fragmented burdens of law)	Law fulfilled through love; salvation not by extensive legal speech
Exegetical Purpose	Anti-Marcionite argument: Creator foretold simplification of covenantal economy	Catechetical/apologetic argument: prophecy anticipates concise salvation through Christ
Conceptual Function	Shortened divine word = compressed new covenant revelation	Shortened divine word = salvific principle summarized in faith/love
Structural Role in Argument	Opening methodological statement for Book IV (Luke commentary framework)	Demonstration of prophetic anticipation of Christian salvation economy