"On Holy Saturday the Church waits at the Lord's tomb in prayer and fasting, meditating on his Passion and Death and on his Descent into Hell, and awaiting his Resurrection. The Church abstains from the Sacrifice of the Mass, with the sacred table left bare, until after the solemn Vigil, that is, the anticipation by night of the Resurrection, when the time comes for pashal joys, the abundance of which overflows to occupy fifty days."
"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.'" (CCC628)
--From our Daily Roman Missal, Third Edition, Large Print