The Beatitudes depict the countenance of Jesus Christ and portray his charity. They express the vocation of the faithful associated with the glory of his Passion and Resurrection; they shed light on the actions and attitudes characteristic of the Christian life; they are the paradoxical promises that sustain hope in the midst of tribulations; they proclaim the blessings and rewards already secured, however dimly, for Christ's disciples; they have begun in the lives of the Virgin Mary and all the saints.
Source: Catechism of the Catholic Church (Vatican.va)