A sacrament is an “efficacious sign of grace, instituted by Christ and entrusted to the Church, by which divine life is dispensed to us through the work of the Holy Spirit” (Catechism of the Catholic Church774, 1131).
“The seven sacraments touch all the stages of Christian life: they give birth and increase, healing and mission to the Christian’s life of faith. There is thus a certain resemblance between the stages of natural life and the stages of the spiritual life” (Catechism 1210).
According to the Second Vatican Council, “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 disposes the faithful most effectively to receive this grace in a fruitful manner, to worship God duly, and to practice charity” (Sacred Constitution on the Liturgy, 59).