Paragraph 20 continues the discussion on the mission of the baptized person. Pope Francis counsels the imitation of Jesus Christ:
That mission has its fullest meaning in Christ, and can only be understood through him. At its core, holiness is experiencing, in union with Christ, the mysteries of his life. It consists in uniting ourselves to the Lord’s death and resurrection in a unique and personal way, constantly dying and rising anew with him. But it can also entail reproducing in our own lives various aspects of Jesus’ earthly life: his hidden life, his life in community, his closeness to the outcast, his poverty and other ways in which he showed his self-sacrificing love. The contemplation of these mysteries, as Saint Ignatius of Loyola pointed out, leads us to incarnate them in our choices and attitudes. [Spiritual Exercises, 102-312] Because “everything in Jesus’ life was a sign of his mystery”, [CCC 515] “Christ’s whole life is a revelation of the Father”, [CCC 516] “Christ’s whole life is a mystery of redemption”, [CCC 517] “Christ’s whole life is a mystery of recapitulation”, [CCC 518] “Christ enables us to live in him all that he himself lived, and he lives it in us”. [CCC 521]
You can check the full document Gaudete et Exsultate on the Vatican website.