The letters that Paul wrote while a prisoner either in Ephesus or in Rome are the latest writings of his that are preserved in the New Testament. They represent his most mature thought concerning the meaning of Christianity and are of special value for that reason. Although he has some things to say with reference to particular problems in local churches, he mainly discusses the significance of Jesus' life in relation to both the salvation of human beings and its place in the scheme of the universe as a whole. The letters are also of interest because they reveal the changes that took place in Paul's own thinking during the years following his conversion to Christianity. Perhaps the most significant change that can be noted in these later writings lies in the fact that Paul no longer talks about the end of the age in terms of Jewish apocalypticism. His teaching emphasizes the quality of living that is made possible when a person's life is transformed by the indwelling presence of the Spirit of Christ.
Some critics maintain that in Paul's later years, he speaks less about the historic Jesus and more about the cosmic Christ. This criticism can be misleading if it suggests that, for Paul, the earthly life of Jesus was unimportant or did not provide the foundation on which Christianity is built. On the other hand, in Paul's judgment, the power of the one and only God of the universe, working in Jesus, makes Jesus' life significant and thus brings to all humanity an opportunity to see how the redemption of humanity can be achieved.
