After His Resurrection Jesus breathed on his apostles and said, “Receive the Holy Spirit”. And we read about the dramatic events on Pentecost. Finally, we have examples of the Apostles conferring the Holy Spirit on others. Confirmation is a “perfection” of the grace of baptism. It is customary for the Sacrament to be administered by a bishop, but with the bishop's permission, a priest can also administer it. The essential part of the Sacrament is the anointing with oil, and the words, “Receive the Holy Spirit.”
Confirmation can only be received once. Like Baptism and Holy Orders it causes a permanent change in our relationship with God and the Church. It is generally administered to mature Catholics – teenagers and older.
The sacrament roots us more firmly in our relationship to God the Father as sons and daughters; it increases in us the gifts of the Holy Spirit (wisdom, understanding, wonder and awe (fear of the Lord), counsel, knowledge, fortitude, and piety (reverence), and it binds us more closely to the Church, giving us the strength to defend our faith by word and action.
Confirmation must be received in order to receive Holy Orders, and is strongly recommended to those who are about to receive the sacrament of Matrimony.