The observance of the Baptism of Our Lord offers the opportunity to reflect on the significance of Baptism in the life of a Christian. What exactly occurs when water and the Word are applied to a sinful human being? Luther addressed this life-giving Sacrament in a sermon on John 20:19–31 included in his Church Postil, though the passage the reformer focuses on in this section is 1 John 5:6: “This is the one who comes with water and blood.”
St. John . . . says about Christ: “This is the one who comes with water and blood” [1 John 5:6], etc. He includes what we have in the kingdom of Christ and praises the power of our dear Baptism and of the suffering or blood of Christ. He brings and fastens everything together in one bundle and produces a third part out of the testimony, so that all three are together at the same time and with each other testify to and confirm our faith—namely, the water, the blood, and the Spirit.
The first [of these three] is that Christ comes with water (that is, holy Baptism). He uses this as an outward sign for His work of the new birth and sanctification of man. This water with which Christ comes must not be merely an empty sign, for He comes not only to wash or bathe the body but also to cleanse the whole man from all the filth and defects innate in us from Adam. . . . Christ came with a new water bath and Baptism, which is not a mere external washing away of bodily uncleanness but a bath which cleanses man of the inward filth of his old sinful birth and from an evil conscience. It brings him the forgiveness of sins and a good conscience toward God, as St. Peter says [1 Pet. 3:21]. . . .
He began this Baptism through John the Baptist, and in order to distinguish it from the old Mosaic and Jewish baptism and bathing, He called it “a Baptism for repentance and the forgiveness of sins” [Mark 1:4; Luke 3:3]. That means that man recognizes his inner uncleanness and knows that the external Mosaic cleanness is of no help before God; cleansing of the conscience and the forgiveness of sins must be sought and received through the power of the Lord Christ, who instituted Baptism.
The second [of the three]: If that is to happen in us through Baptism, then there must be not merely plain water there, for otherwise it could do no more than any other water bath or Jewish and Turkish baptizing and bathing. Rather, there must be a power and might there which can inwardly cleanse people according to the soul. Therefore, Christ comes (says St. John) not only with water but also with blood—not with the blood of oxen or calves and goats, which were the sacrifices of the Old Testament, but with His own blood, as St. Paul says (Hebrews 9 [:12]). He comes through the preaching office of the New Testament (which is His government on earth), imparts to us the power and working of His sacrifice and blood which He poured out for our sins, and thus gives us the treasure with which He purchased our redemption.
Therefore, in Baptism there is the power of the blood of Christ, which is the true caustic soap that not only washes away filth from the skin of the body but also eats through, cleanses, and washes out the inner filth, so that the heart becomes pure before God. Thus the blood of Christ is powerfully mixed into the water of Baptism, so that we should not look at it or regard it as being plain water, but rather as already dyed and reddened with the precious, rose-colored blood of the dear Savior, Christ. . . .
The third part which St. John adds to these two is the Spirit, who testifies together with the other two and even works through the water and the blood. This is the Holy Spirit Himself, not the way He is above, invisibly in the divine essence, but as He becomes manifest and is heard through the external office and Word. St. John even says that He, together with the other two, “testifies on earth” [1 John 5:8], etc.
Only this Christ brings with Him the Holy Spirit and His power. He sanctifies us through the blood and water which flow from His divine side. He makes us partakers of this through the external preaching office and the Sacraments, which are called the Holy Spirit’s office and gifts. Through these He works in His Christendom. . . .
This work of the Holy Spirit is received and perceived in no other way than through faith in this testimony or preached Word of Christ, if the heart grasps this and considers it certain that it is and happens in him as the Word says. Thus those who are in the holy bath of water and of the blood of Christ are truly cleansed and born anew through the Holy Spirit.
Amended from Luther’s Works volume 77, pages 121–23. © 2014 Concordia Publishing House. All rights reserved.
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