What is the Sacrament of Confirmation?

While the Sacrament of Confirmation is a Sacrament of Initiation (along with baptism and the Eucharist). While it is the end of initiation, confirmation is never really meant to be an ending, but the start of something new. It is a kind of personal Pentecost, a fresh outpouring of the Holy Spirit in our hearts that makes us doers of the Word of God, not hearers only. Confirmation completes the good work that was begun in baptism and that is continually strengthened in receiving the Eucharist.

When the day of Pentecost had come, they were all together in one place. And suddenly a sound came from heaven like the rush of a mighty wind, and it filled all the house where they were sitting. And there appeared to them tongues as of fire, distributed and resting on each one of them. And they were all filled with the Holy Spirit and began to speak in other tongues, as the Spirit gave them utterance.

Acts 2:1-4