CATECHISM OF THE CATHOLIC CHURCH
SECOND EDITION

Paragraphs 1006–1009

1006 "It is in regard to death that man's condition is most shrouded in doubt." In a sense bodily death is natural, but for faith it is in fact "the wages of sin." For those who die in Christ's grace it is a participation in the death of the Lord, so that they can also share his Resurrection.
1007 Death is the end of earthly life. Our lives are measured by time, in the course of which we change, grow old and, as with all living beings on earth, death seems like the normal end of life. That aspect of death lends urgency to our lives: remembering our mortality helps us realize that we have only a limited time in which to bring our lives to fulfillment:

Remember also your Creator in the days of your youth, . . . before the dust returns to the earth as it was, and the spirit returns to God who gave it.

1008 Death is a consequence of sin. The Church's Magisterium, as authentic interpreter of the affirmations of Scripture and Tradition, teaches that death entered the world on account of man's sin. Even though man's nature is mortal God had destined him not to die. Death was therefore contrary to the plans of God the Creator and entered the world as a consequence of sin. "Bodily death, from which man would have been immune had he not sinned" is thus "the last enemy" of man left to be conquered.
1009 Death is transformed by Christ. Jesus, the Son of God, also himself suffered the death that is part of the human condition. Yet, despite his anguish as he faced death, he accepted it in an act of complete and free submission to his Father's will. The obedience of Jesus has transformed the curse of death into a blessing.