The document provides information about the sacred liturgy and sacraments of the Catholic Church. It defines the sacred liturgy as the true worship of God enacted by Jesus Christ and his body, the Church, through ceremonies, rites and formulas established by Scripture and Tradition. It explains that the Church celebrates liturgy in obedience to God's will and that liturgy is fitting for humans as social beings. Major liturgies include the sacraments and the Divine Office, and they are celebrated at fixed times and seasons, most importantly relating to the life of Christ.