59 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 impart grace, but, in addition, the very act of celebrating them most effectively disposes the faithful to receive this grace in a fruitful manner, to worship God duly, and to practice charity. It is therefore of the highest importance that the faithful should easily understand the sacramental signs, and should frequent with great eagerness those sacraments which were instituted to nourish the Christian life.
Source: Sacrosanctum Concilium (Vatican.va)