"The purpose of the sacraments is to sanctify men, to build up the Body of Christ, and, finally, to give worship to God. Because they are signs they also instruct. They not only presuppose faith, but by words and objects they also nourish, strengthen, and express it. That is why they are called 'sacraments of faith.' They do, indeed, confer grace but, in addition, the very act of celebrating them most effectively disposes the faithful to receive this grace to their profit, to worship God duly, and to practice charity.
It is, therefore, of the greatest importance that the faithful should easily understand the sacramental signs, and should eagerly frequent those sacraments which were instituted to nourish the Christian life." (Constitution on the Sacred Liturgy, #59, from Documents on the Liturgy, 1963-1979: Conciliar, Papal, and Curial Texts, copyright 1982, ICEL)
To read what the Catechism of the Catholic Church teaches about sacraments, click here.