This lesson continues the previous one and examines the theological and practical aspects of the Church's liturgy. The liturgy is the summit of the Church's activity and the font from which all her power flows. It is our participation in God's work. The Trinitarian dimension of the liturgy: the Father is its source and goal; in it the Messiah continues his work of redemption through the Holy Spirit, which makes it efficacious. The seven sacraments are the powers of the Messiah which now work in the Church. The participants in the liturgy and how it is celebrated. The forms of the liturgy. Liturgical times and seasons.