The Christian begins his day, his prayers, and his activities with the Sign of the Cross: “in the name of the Father and of the Son and of the Holy Spirit. Amen.” The baptized person dedicates the day to the glory of God and calls on the Savior’s grace which lets him act in the Spirit as a child of the Father. The sign of the cross strengthens us in temptations and difficulties.
Catechism of the Catholic Church 2157
Worship of the Eucharist. In the liturgy of the Mass we express our faith in the real presence of Christ under the species of bread and wine by, among other ways, genuflecting or bowing deeply as a sign of adoration of the Lord.
Catechism of the Catholic Church, 1378