What is Chrism Mass?
This Mass, which the bishop concelebrates with his college of presbyters and at which he consecrates the holy chrism and blesses the other oils, manifests the communion of the presbyters with their bishop.
The Holy Chrism consecrated by the bishop is used to anoint the newly baptized, to seal the candidates for Confirmation, and to anoint the hands of presbyters and the heads of bishops at their ordination, as well as in the rites of anointing pertaining to the dedication of churches and altars. Chrism is a sign.
By Baptism Christians are plunged into the paschal mystery of Christ; they die with him, are buried with him, and rise with him; they are sharers in his royal and prophetic priesthood.
By Confirmation, Christians receive the spiritual anointing of the Spirit who is given to them.
By the Oil of Catechumens, the effect of the baptismal exorcisms is extended. Before they go to the font of life to be reborn, the candidates for baptism are strengthened to renounce sin and the devil.
By the use of the Oil of the Sick, to which Saint James is a witness, the sick receives a remedy for the illness of mind and body, so that they may have strength to bear suffering and to resist evil and obtain the forgiveness of sins.
This Mass, therefore, is a clear expression of the unity of the priesthood and the sacrifice of Christ, which continue to be present in the Church.
-Excerpts from the Ceremonial of Bishops and The Blessings of Oils and Chrism