The immortality of the soul is an opinion - the resurrection of the dead is a hope. The first is a trust in something immortal in the human being, the second a trust in the God who calls into being the things that are not, and makes the dead live. In trust in the immortal soul we accept death, and in a sense anticipate it. In trust in the life-creating God we await the conquest of death - 'death is swallowed up in victory' (I Cor. 15.54) - and an eternal life in which 'death shall be no more' (Rev. 21.4). The immortal soul may welcome death as a friend, because death releases it from the earthly body; but for the resurrection hope, death is 'the last enemy' (I Cor. 15.26) of the living God and the creations of his love (Minneapolis: Fortress, 1996, 65-66).
In short, the immortality of the soul is not a Christian doctrine. Resurrection of the body is.