The Scriptures had foretold this divine plan of salvation through the putting to death of "the righteous one, my Servant" as a mystery of universal redemption, that is, as the ransom that would free men from the slavery of sin. Citing a confession of faith that he himself had "received", St. Paul professes that "Christ died for our sins in accordance with the scriptures." In particular Jesus' redemptive death fulfills Isaiah's prophecy of the suffering Servant. Indeed Jesus himself explained the meaning of his life and death in the light of God's suffering Servant. After his Resurrection he gave this interpretation of the Scriptures to the disciples at Emmaus, and then to the apostles.
-- CCC 601