Jesus was baptized to publicly enter his messianic mission as the obedient Son, identifying himself with the sinful people he came to save, and “fulfilling all righteousness” as their representative head.[desiringgod]
Matthew’s explicit reason is Jesus’ own statement to John: “for thus it is fitting for us to fulfill all righteousness” Matt3:15Matt 3:15Matt3:15.[thegospelcoalition]
In Reformed and Reformed Baptist theology, this is read as covenantal, representative obedience: Jesus undergoes every righteous requirement of God’s will on behalf of those he came to redeem, as the last Adam and true Israel.[thegospelcoalition]
John’s baptism was a “baptism of repentance” for Israel, a visible call to confess sin, turn to God, and await the coming One.[desiringgod]
Though sinless, Jesus steps into that line of repentant Israel, not because he personally needs repentance, but because he identifies with the people whose sins he will bear, entering their place under the sign appointed for them.[thegospelcoalition]
An illustration used in contemporary Reformed exposition is that Jesus stands in the place in the river where guilty Israel ought to stand, so that all he does there—submitting, being anointed, being declared the beloved Son—is done for them.[thegospelcoalition]
Many Reformed and Reformed Baptist writers explicitly connect Jesus’ baptism with the doctrine of “alien righteousness”: those who are unrighteous must receive a righteousness not their own, provided by Christ’s lifelong obedience.[learn.ligonier]
On this reading, Jesus accepts the baptism that belongs to repentant sinners and perfectly obeys in their stead, so that all who are united to him by faith share in the righteousness he “fulfills,” including his submission in baptism.[learn.ligonier]
This is often tied to Paul’s language that Christ was “made to be sin” for us so that we might become “the righteousness of God in him”; Jesus’ acceptance of a sinner’s baptism anticipates this representational exchange.[learn.ligonier]
Jesus’ baptism functions as the public inauguration of his messianic ministry: heavens opened, the Spirit descends, and the Father’s voice declares him the beloved Son.[thegospelcoalition]
Reformed theology sees this as his visible anointing with the Spirit for his prophetic, priestly, and kingly office, the moment when he steps out of obscurity into his role as the Christ who will suffer, obey, and save.[thegospelcoalition]
Some Reformed expositors note that what is uniquely manifest in Jesus’ baptism—the advent of the Spirit—becomes broadly true for Christian baptism, which is now a sign of union with the crucified and risen Christ in the Spirit’s power.[reformation21]
A common strand of Reformed and Baptist interpretation sees Jesus’ immersion as a prophetic sign of his coming death, burial, and resurrection.[learn.ligonier]
His going down into the water and coming up again symbolizes the pattern later expounded in Romans 6: believers are baptized into Christ’s death and raised with him, and Jesus’ own baptism stands at the head of that pattern, prefiguring the cross and empty tomb.[learn.ligonier]
Thus, his baptism is not merely ethical or exemplary; it is eschatological and typological, foreshadowing the climactic act by which he will bear sin and bring new life.[learn.ligonier]