Confirmation perfects Baptismal grace; it is the sacrament which gives the Holy Spirit in order to root us more deeply in the divine filiation, incorporate us more firmly into Christ, strengthen our bond with the Church, associate us more closely with her mission, and help us bear witness to the Christian Faith in words accompanied by deeds.
-Catechism of the Catholic Church, 1316
By the sacrament of Confirmation they are more perfectly bound to the Church and are endowed with the special strength of the Holy Spirit.
-Lumen Gentium 11