Catechism of the Catholic Church

The Holy Spirit, who instructs us to celebrate the liturgy in expectation of Christ's return, teaches us to pray in hope. Conversely, the prayer of the Church and personal prayer nourish hope in us. The psalms especially, with their concrete and varied language, teach us to fix our hope in God: "I waited patiently for the LORD; he inclined to me and heard my cry." As St. Paul prayed: "May the God of hope fill you with all joy and peace in believing, so that by the power of the Holy Spirit you may abound in hope."