By water and blood.
This they commonly explain in various ways. Most interpreters turn their attention to the two sacraments, because when Christ's side was opened, water and blood flowed out.9 Although this explanation does not displease me, yet I simply take this statement to mean Baptism, provided that it is applied in the right way, so that the very sprinkling of the blood of Christ comes to us. For the blood is considered in two ways. First it is shed10 physically, then spiritually, as Peter says in 1 Peter 1:2, for the called saints in the sprinkling of the blood of Christ. This is the application of the blood of Christ; this is the value of the shedding. For He comes to me through the Word and is received through the Word and faith. And thus the blood that was sprinkled physically cleanses and washes me spiritually. Thus this meaning can stand, namely, so that Christ's blood is rightly distributed and applied. For Christ does not come through water alone; He comes through water joined with the blood, that is, through Baptism, which is colored with the blood. Otherwise the blood is of no use, unless you believe that this blood was shed for you. For John came by water alone when he was baptizing into the Christ who was to come. Yet he also came by blood, for the water of Baptism is sanctified through the blood of Christ. Therefore it is not plain water; it is water stained with blood because of this blood of Christ which is given to us through the Word, which brings with it the blood of Christ And here we are said to be baptized through the blood of Christ, and thus we are cleansed from sins. For the water alone does not cleanse us from sins. By this text all human powers and efforts are condemned. The Antichrist comes with his efforts, but the blood of Christ does not profit him at all. The Jew comes with his ceremonies; but the blood of Christ does not profit him either. But those who follow Christ come by water and blood, that is, through Baptism; and thus they enter into the kingdom of Christ. Therefore the new spirits, who ridicule Baptism and invent new ways, are completely in error. They call it a dog's bath.11 This is not surprising. They have only water, but we have blood in addition to the water.