Catholic Commentary
God's Purpose in Magnifying the Law
21It pleased Yahweh, for his righteousness’ sake, to magnify the law and make it honorable.
Isaiah 42:21 states that God was pleased, for the sake of his righteousness, to magnify the law by revealing its true depth and glory through his Servant. This verse grounds the Servant's mission in God's own covenant fidelity and moral integrity rather than external necessity, pointing ultimately to Christ's perfect fulfillment and embodiment of the law's interior demands.
God doesn't preserve the law reluctantly—He delights in it and magnifies it, which is precisely what Christ does when He reveals its innermost spiritual demands and fulfills it perfectly on the cross.
St. Paul's treatment of the law in Romans further illuminates this verse. In Romans 3:31, Paul insists: "Do we then overthrow the law by this faith? By no means! On the contrary, we uphold the law." For Paul, as for Isaiah, the law is not cancelled by the advent of grace but brought to its intended fullness and glory through the righteousness of God revealed in Christ (Rom 1:17; 3:21–26).
Catholic tradition reads Isaiah 42:21 as one of Scripture's most concentrated statements about the relationship between divine righteousness, law, and redemption — a relationship that reaches its fulfillment in Jesus Christ and finds its ongoing life in the Church.
The Church Fathers were attentive to this verse's Christological weight. St. Justin Martyr (Dialogue with Trypho, 65) identifies the Servant of Isaiah 42 as Christ and reads his magnifying of the law as the inauguration of the New Covenant, in which the Torah is written not on stone but on the heart (cf. Jer 31:33). St. Irenaeus (Adversus Haereses IV.34) argues against Marcionite rejection of the Old Law precisely on the grounds that Christ "expanded and filled out" the commands of the law, showing their fuller spiritual demands — a direct echo of gadal.
The Catechism of the Catholic Church teaches that "Jesus did not abolish the Law of Sinai, but rather fulfilled it (cf. Mt 5:17–19) with such perfection (cf. Jn 8:46) that he revealed its ultimate meaning (cf. Mt 5:33) and redeemed the transgressions against it (cf. Heb 9:15)" (CCC §592). This magisterial statement is precisely the New Testament interpretation of Isaiah 42:21: the law is not discarded but brought to its God-intended fullness.
St. Thomas Aquinas (Summa Theologiae I-II, Q. 107, a.2) distinguishes between the ceremonial, judicial, and moral precepts of the Old Law, arguing that Christ fulfills each in a distinct mode. The moral law — rooted in natural law and ultimately in eternal law — is not merely preserved but elevated and interiorized by Christ's grace, which is the gift of the Holy Spirit enabling what the letter of the law could only command.
Vatican II's Dei Verbum (§16) teaches that "the books of the Old Testament...attain and show forth their full meaning in the New Testament." Isaiah 42:21 is a paradigmatic case: its meaning is partially disclosed in Israel's history, but its fullest referent is Christ, whose righteousness alone can truly "magnify" the law by filling it with his own person.
For a contemporary Catholic, Isaiah 42:21 speaks directly against two perennial temptations: antinomianism (dismissing moral and divine law as irrelevant to a life of grace) and legalism (reducing the law to external compliance without interior transformation).
The verse reminds us that God's law — including the moral teaching of the Church — is not an arbitrary imposition but an expression of God's own righteousness, given out of delight and love. When Catholics engage with the Church's moral teaching on life, marriage, justice, or worship, they are not submitting to bureaucratic rule-keeping. They are participating in something God Himself "takes pleasure in" and wishes to "magnify."
Practically, this passage invites the Catholic to ask: Do I experience God's commandments as something to be minimized and negotiated around, or as something to be magnified — explored in their depth, lived in their fullness, embraced in their beauty? The Servant's mission is to bring the law's full light to bear on human life. The Catholic disciple, configured to Christ through baptism, shares in that same mission: to witness to the beauty of God's law in a culture that has largely abandoned it.
Commentary
Literal Meaning and Context
Isaiah 42:21 arrives near the close of the first Servant Song (Isa 42:1–9) and its immediate aftermath (vv. 10–25), a passage in which Yahweh presents His chosen Servant, pours out His Spirit upon him, and commissions him to bring forth justice to the nations. Verse 21 functions as a hinge statement: it offers the divine rationale behind the entire Servant mission by grounding it not in human achievement but in Yahweh's own righteousness (tsedaqah).
"It pleased Yahweh" — The Hebrew verb chaphetz (to delight in, to take pleasure in) signals a free, sovereign, and deeply personal divine initiative. This is not obligation but love. God is not compelled by external necessity to act; He acts from within the plenitude of His own righteous character. The Septuagint renders this with eboulēthē, "he willed it," emphasizing the volitional, purposeful nature of God's action — language that the New Testament will echo in the context of Christ's incarnation and sacrifice (cf. Heb 10:7, citing Ps 40:8: "I have come to do your will, O God").
"For his righteousness' sake" — This phrase, lema'an tsidqo, is critical. God's motivation is interior — it springs from who He is, not from what humanity deserves. The righteousness here is not primarily forensic (a verdict of acquittal) but ontological and covenantal: it is God's covenant fidelity, His absolute moral integrity, and His burning commitment to set all things right. This anchors the law's magnification not in legalism but in divine love ordered toward justice.
"To magnify the law" — The verb gadal (to make great, to magnify, to glorify) applied to Torah is extraordinary. God does not merely preserve, transmit, or enforce the law — He glorifies it. The Masoretic text uses Torah in its fullest sense: not a narrow legal code but the whole of divine instruction, revelation, and covenantal wisdom. To "magnify" the Torah means to show its true depth and range, to demonstrate its inner coherence and beauty, to elevate it beyond the distortions of casuistry and hypocrisy. This is precisely what the Servant will do: he will not cry aloud in the streets (v. 2), but by his very person and mission he will reveal what the law truly is and truly asks of humanity.
Typological and Spiritual Senses
Patristically and typologically, this verse points directly to Jesus Christ as the Servant who fulfills it. In the Sermon on the Mount (Matt 5:17–20), Christ explicitly frames his mission in terms that echo Isaiah 42:21: "Do not think that I have come to abolish the Law or the Prophets; I have not come to abolish them but to fulfill () them." The Greek — to fill to the full, to bring to completion — is the New Testament's interpretive translation of . Christ magnifies the law by embodying it perfectly, by teaching its interior demands (the Antitheses of Matt 5), and ultimately by fulfilling its sacrificial logic on the cross.