23. Christ comes, first, "by water"; that is, by holy baptism. He employs baptism as an outward sign of his work in the new birth of man and in man's sanctification. This water by which Christ comes cannot be a mere, empty sign; for he comes not merely to cleanse or bathe the body with water, but to purify the whole man from all pollution and blemishes inherent in him from Adam. Christ has instituted a cleansing wholly unlike the Mosaic ablutions under the Old Testament dispensation. Moses came with various laws relating to washings and purifications, but they were only cleansings of the body or of the flesh and had daily to be repeated. Now, since these ceremonials contributed nothing to man's purification in God's sight—a thing to be effected by nothing short of a new birth—Christ came with a new order of cleansing, namely, baptism, which is not a mere external ablution from physical impurities, but a washing effective in man's purification from the inward pollution of his old sinful birth and from an evil conscience, and bringing remission of sin and a good conscience toward God, as Peter says. 1 Pet 3, 21. Paul, also (Tit 3, 5), calls baptism the "washing of regeneration and renewing of the Holy Spirit."
24. Christ first instituted baptism through John the Baptist. To distinguish it from the Mosaic baptism, the old Jewish rite of washings, Christ styles it "a baptism unto repentance and the remission of sins." He designs that therein man shall perceive his inner impurities and know them to be, in God's sight, beyond the power of outward Mosaic ablutions to reach; shall know also that purification of the conscience and remission of sins must be sought and obtained through the power of Christ the Lord, who instituted baptism.
25. Secondly, that this cleansing of sin may be effected in us through baptism, something more than mere water must be present. Mere water could effect no more than do ordinary washings, and no more than Jewish and Turkish baptisms and washings effect. There must be a power and force accompanying the water effective to work inward purification, the purification of the soul. Therefore, John says, Christ came, not by water alone, but also by blood; not the blood of bulls, or of calves, or of goats, those Old Testament sacrifices, but his own blood, as Paul declares. Heb 9, 12. He comes through the preaching office of the New Testament, which is his rule upon earth, imparts to us the effective power of his shed blood, his sacrifice for our sins, and thus applies to us the treasure wherewith he purchased our redemption.
26. Hence there is now in baptism this efficacy of the blood of Christ. That is the true caustic soap which not only removes the uncleanness of the outer man, but penetrates to the inner nature, consuming its impurities and cleansing them away, that the heart may become pure in God's sight. Thus, the blood of Christ is so effectively mingled with the baptismal water that we must not regard it as mere water, but water beautifully dyed with the precious crimson blood of our dear Saviour, Christ. Baptism, then, cannot rightly be regarded a physical cleansing, like the Mosaic ablutions, or like the cleansing the bathhouse affords; it is a healing baptism, a baptism or washing with blood, instituted by none but Christ, the Son of God, and that through his own death.
27. In the record of Christ's passion, careful note is made of the fact that blood and water flowed immediately from the spear-thrust in Christ's side as he hung upon the cross; it is pointed out as a special miracle. The design there is to teach that Christ's shed blood is not without significance, but stands for a washing or bath whose efficacy is present in the baptism with water; and that from the slain body of Christ issues an unceasing stream of water and blood, flowing on down through the entire Christian Church, wherein we must all be cleansed from our sins. What makes baptism so precious, so holy and essential is the mingling and union of the water with the blood of Christ; to be baptized into Christ with water is really to be washed and cleansed with the blood of Christ.