"The sacraments are outward signs instituted by Christ to give grace. Signs, there are all kinds of signs around us but sacraments are unique as signs because they are signs of the presence and love of God for us and of our desire to come in contact or encounter God." (Msgr. Zenz from the "Introduction to the Sacraments" video.)
In this video series Msgr. John Zenz, of the Archdiocese of Detroit, walks us through the seven sacraments of the church.
The Catechism of the Catholic Church teaches that the Sacraments are "efficacious signs of grace, instituted by Christ and entrusted to the Church, by which divine life is dispensed to us. The visible rites by which the sacraments are celebrated signify and make present the graces proper to each sacrament. They bear fruit in those who receive them with the required dispositions.