The final thing to be concluded from the words of Jesus is that the martyr suffers with Christ as a member of the mystical body of Christ. When we say that the martyr suffers with Christ, we mean that his suffering is not described fully by simply saying that he suffers for Christ. Many soldiers have died for their king. But the martyr's death differs from the soldier's death in that the martyr does not only suffer for Jesus, rather he is led into his own death by the death of Christ. The passion and death of Christ, because it is "the Son of man," the one who became man, who suffers, extends over the entire Church as his mystical body. Therefore the one who confesses Jesus in baptism is baptized into the death of Jesus, and therefore too the one who gives thanks to God in the Eucharist for having sent us his son Jesus participates in Jesus, in that he eats the broken body of the Lord and drinks the cup with the blood of the New Covenant. Because we are baptized into the death of the Lord and are fed with the blood of the Lord, it is unavoidable for everyone who belongs to the Church to have a share in the suffering of Christ....  baptism by water and baptism by blood come from the same Lord, prefigured in the symbol, as Cyril of Jerusalem has shown, of the blood and water that flowed from the side of Jesus.

Erik Peterson, Witness to the Truth