Catholic Commentary
Paul's Sermon: Salvation History from the Exodus to John the Baptist (Part 2)
24before his coming, when John had first preached the baptism of repentance to Israel.25As John was fulfilling his course, he said, ‘What do you suppose that I am? I am not he. But behold, one comes after me, the sandals of whose feet I am not worthy to untie.’
Acts 13:24–25 presents Paul's account of John the Baptist as a herald preparing Israel for Jesus's arrival through preaching baptism of repentance. John explicitly denies being the Messiah and humbly claims he is unworthy to untie the sandals of the one coming after him, expressing Christ's supreme dignity and his own subordinate role as a messenger.
The Baptist stands at the threshold of two covenants, the final voice of the old and the closest witness of the new—his complete self-erasure reveals the infinite distance between herald and King.
The sandal-unfastening image is calibrated with great care. In first-century Jewish custom, untying a master's sandals was the task of the lowest household slave — a deed considered too menial even for a disciple to perform for his rabbi (cf. b. Ketubbot 96a). John does not merely say he is Christ's servant; he says he is unworthy to perform the most degraded act of service available. This is a Christological declaration of the highest order: the one coming is not simply greater than John in degree but in kind — he belongs to a different ontological register. Origen, in his Commentary on John, notes that John's very humility is itself a form of witness, because one can only be humbled by what is genuinely greater; the depth of John's debasement reveals the height of Christ's dignity.
Catholic tradition reads these verses within a richly layered theology of prophecy and fulfillment. The Catechism teaches that John the Baptist "comes to complete the cycle of prophets begun by Elijah" and is "more than a prophet" precisely because he does not merely foretell but points with his finger: "Behold, the Lamb of God" (CCC 719–720). John stands at the exact threshold between two covenants — the last and greatest voice of the Old, the first and closest witness of the New.
St. Augustine, in his Sermon 293, draws the contrast vividly: "John is the voice, but the Lord is the Word who was in the beginning. John is a voice that lasts for a time; from the beginning Christ is the Word who lives for ever." This Augustinian distinction — vox (voice) and Verbum (Word) — became a cornerstone of patristic Christology and shapes how Catholic liturgy presents John at Advent and on his feast day (June 24).
The sandal-untying image carries typological depth as well. St. Ambrose (De Mysteriis 4.23) connects it to the shoe of Boaz's kinsman-redeemer in Ruth 4:7-8, reading it as a figure of one who cedes the rights of redemption to another — Christ being the true Kinsman-Redeemer of humanity. Similarly, Moses' removal of sandals before the burning bush (Exod 3:5) — standing on holy ground — is a patristic type for the holiness of the one whose sandals cannot be touched.
For Catholic systematic theology, Paul's sermon here demonstrates the sensus plenior of Israel's scriptures: John's preaching of repentance baptism was not a dead end but a divinely ordered preparation (Latin: praeparatio evangelica), confirming Vatican II's teaching in Dei Verbum §14–15 that the Old Covenant was ordered toward and finds its fulfillment in Christ.
These verses offer contemporary Catholics a precise antidote to a pervasive spiritual confusion: the conflation of the messenger with the message, or the minister with Christ. In an age of celebrity Christianity — where the personality of the preacher, the podcast host, or the spiritual influencer can eclipse the One being proclaimed — John's self-erasure is a counter-cultural model for every vocation of service. Whether one is a deacon preaching the Gospel, a catechist preparing children for First Communion, a prayer group leader, or a parent handing on the faith, the Baptist's question — "What do you suppose that I am?" — is a question every minister ought to ask of themselves regularly.
More concretely, John's description of himself as finishing his course invites a daily examination of purpose: Am I running my particular race, or have I been distracted into running someone else's? The Advent liturgy returns to John precisely because the Church knows that every Christian life, not just every Advent season, needs a recurring moment of reorientation — away from self-importance, toward the One whose sandal we are not worthy to touch. The sacrament of Reconciliation is one concrete place where this reorientation occurs, mirroring John's baptism of repentance as preparation for encounter with the living Christ in the Eucharist.
Commentary
Acts 13:24 — "Before his coming, when John had first preached the baptism of repentance to Israel"
Paul is mid-sermon in the synagogue of Pisidian Antioch (Acts 13:14–41), rehearsing salvation history from the Exodus through the judges and kings to David, whose lineage produces the Savior (v. 23). Having announced Jesus as the promised descendant of David, Paul does not leap immediately to the resurrection; he pauses to account for John the Baptist. The phrase "before his coming" (Greek: pro prosōpou tēs eisodou autou, literally "before the face of his entrance") is charged with the language of royal procession — a herald runs before the king's face to announce his arrival. John is thus the final outrider of a long monarchical processional stretching back to Moses and the prophets.
The phrase "baptism of repentance" (baptisma metanoias) is precise. John's baptism is not Christian sacramental Baptism — the Catechism distinguishes them clearly (CCC 720) — but a ritual of moral conversion and national preparation, drawing on Old Testament purification rites and the prophetic demand for interior renewal (cf. Ezek 36:25–26). The textual variant noted — "to all the people of Israel" (TR, NU) — broadens the scope deliberately: this is not a sectarian movement but a summons to the entire covenant people to ready themselves. Paul's citation of this detail to a synagogue audience is rhetorically pointed: Israel was already being prepared by its own prophet for the very Jesus Paul is now preaching.
Acts 13:25 — "What do you suppose that I am? I am not he. But behold, one comes after me, the sandals of whose feet I am not worthy to untie."
The phrase "as John was fulfilling his course" (plēroō ton dromon) is significant. Dromon — a race, a course — invokes the image of the runner or messenger who exhausts himself in service of his mission. The word recurs in Paul's farewell speech at Miletus (Acts 20:24) when Paul speaks of finishing his own dromos, and again in 2 Timothy 4:7 ("I have finished the race"). Luke deliberately echoes this vocabulary to draw a parallel between the Baptist and Paul himself: both are heralds whose lives are defined by pointing beyond themselves toward Christ.
John's question — "What do you suppose that I am?" — is a rhetorical self-examination, a public renunciation of messianic pretension. The verb hyponoeō implies suspicion or conjecture; the crowd speculated, and John pre-empts their error. His negative self-identification ("I am not he") mirrors the Fourth Gospel's emphatic "He confessed and did not deny it, and he confessed, 'I am not the Christ'" (John 1:20). This is not false modesty but prophetic self-knowledge: John knows his theological location precisely.