Prophet Isaiah (35: 4-7) encourages those "who are of a fearful heart" and proclaims this marvellous newness which experience has confirmed: when the Lord is present the eyes of the blind are reopened, the ears of the deaf unstopped and the lame man leaps like a hart. All things are reborn and all things are revived, for beneficial waters irrigate the desert. The "desert", in Isaiah's symbolic language, can call to mind the tragic events, difficult situations and loneliness that often mark life; the deepest desert is the human heart when it loses the capacity for listening, speaking and communicating with God and with others. Eyes then become blind because they are incapable of seeing reality; ears are closed so as not to hear the cry of those who implore help; hearts are hardened in indifference and selfishness. But now, the Prophet proclaims, all is destined to change; the "dry land" of a closed heart will be watered by a new, divine sap. And when the Lord comes, to those who are fearful of heart in every epoch he says authoritatively: "Be strong, fear not!" (v. 4).
[Pope Benedict, Faul Valley homily Viterbo 6 September 2009]