CATECHISM OF THE CATHOLIC CHURCH
SECOND EDITION

Paragraphs 626–629

626 Since the "Author of life" who was killed is the same "living one [who has] risen", the divine person of the Son of God necessarily continued to possess his human soul and body, separated from each other by death:

By the fact that at Christ's death his soul was separated from his flesh, his one person is not itself divided into two persons; for the human body and soul of Christ have existed in the same way from the beginning of his earthly existence, in the divine person of the Word; and in death, although separated from each other, both remained with one and the same person of the Word.

627 Christ's death was a real death in that it put an end to his earthly human existence. But because of the union which the person of the Son retained with his body, his was not a mortal corpse like others, for "it was not possible for death to hold him" and therefore "divine power preserved Christ's body from corruption." Both of these statements can be said of Christ: "He was cut off out of the land of the living", and "My flesh will dwell in hope. For you will not abandon my soul to Hades, nor let your Holy One see corruption." Jesus' Resurrection "on the third day" was the sign of this, also because bodily decay was held to begin on the fourth day after death.
628 Baptism, the original and full sign of which is immersion, efficaciously signifies the descent into the tomb by the Christian who dies to sin with Christ in order to live a new life. "We were buried therefore with him by baptism into death, so that as Christ was raised from the dead by the glory of the Father, we too might walk in newness of life."
629 To the benefit of every man, Jesus Christ tasted death (cf. Heb 2:9). It is truly the Son of God made man who died and was buried.