Belief in the resurrection of the dead has been an essential element of the Christian faith from its beginnings. "The confidence of Christians is the resurrection of the dead; believing this we live."
How can some of you say that there is no resurrection of the dead? But if there is no resurrection of the dead, then Christ has not been raised; if Christ has not been raised, then our preaching is in vain and your faith is in vain.... But in fact Christ has been raised from the dead, the first fruits of those who have fallen asleep.
Source: Catechism of the Catholic Church (Vatican.va)