Confirmation is the sacrament in which Christ sends the Holy Spirit to make us adult apostles for our faith. We become 'adults', not in physical age or psychological maturity, but spiritually mature, able to share our spiritual life with others. Confirmation is the public expression or celebration of this emerging spiritual maturity.
Confirmation is the completion of baptism, the giving of the full power of a Christian. 'Confirmation' means a strengthening - this sacrament strengthens and increases what we receive at baptism, particularly the power of bearing witness to Christ To emphasize this, the ceremony of confirmation includes a renewal of our baptismal promises. We now become fully fledged members of the Church, lay apostles in the fullest sense.
The sign or ceremony of Confirmation is the imposition of the Bishop's hands and anointing of the forehead with Chrism., The bishop (or in some cases, the priest) 'lay their hands' on those being confirmed - the ancient biblical gesture by which the gift of the Spirit is invoked. Then the bishop anoints the forehead of each with Chrism (a perfumed oil blessed by the bishop), and says, "N., be sealed with the Holy Spirit, the gift of the Father."