Sacraments are the visible signs of the invisible grace which is given to us through the death and resurrection of our Lord Jesus Christ.
"By his divine power, he has lavished on us all the things we need for life and for true devotion, through the knowledge of him who has called us by his own glory and goodness. 4 Through these, the greatest and priceless promises have been lavished on us, that through them you should share the divine nature and escape the corruption life in the world through disordered passion." (2 Peter 1:3-4)
As she has done for the canon of Sacred Scripture and for the doctrine of the faith, the Church, by the power of the Spirit who guides her “into all truth,” has gradually recognized this treasure received from Christ and, as the faithful steward of God’s mysteries, has determined its “dispensation.” Thus the Church has discerned over the centuries that among liturgical celebrations there are seven that are, in the strict sense of the term, sacraments instituted by the Lord. (Catechism of the Catholic Church, 1117)
The sacraments are “of the Church” in the double sense that they are “by her” and “for her.” They are “by the Church,” for she is the sacrament of Christ’s action at work in her through the mission of the Holy Spirit. They are “for the Church” in the sense that “the sacraments make the Church,” since they manifest and communicate to men, above all in the Eucharist, the mystery of communion with the God who is love, One in three persons. (Catechism of the Catholic Church, 1118)