Catechism of the Catholic Church

Thus the risen Christ, by giving the Holy Spirit to the apostles, entrusted to them his power of sanctifying: they became sacramental signs of Christ. By the power of the same Holy Spirit they entrusted this power to their successors. This "apostolic succession" structures the whole liturgical life of the Church and is itself sacramental, handed on by the sacrament of Holy Orders. (861, 1536)