Catechism of the Catholic Church
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." 474
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.
630 During Christ's period in the tomb, his divine person continued to assume both his soul and his body, although they were separated from each other by death. For this reason the dead Christ's body "saw no corruption" (Acts 13:37).
English Translation of the Cathechism of the Catholic Church for the United States of America © 1997, United States Catholic Conference, Inc.