"You are the light of the world...". For those who first heard Jesus, as for us, the symbol of light evokes the desire for truth and the thirst for the fullness of knowledge which are imprinted deep within every human being.
When the light fades or vanishes altogether, we no longer see things as they really are. In the heart of the night we can feel frightened and insecure, and we impatiently await the coming of the light of dawn. Dear young people, it is up to you to be the watchmen of the morning (cf. Is 21:11-12) who announce the coming of the sun who is the Risen Christ!
The light which Jesus speaks of in the Gospel is the light of faith, God's free gift, which enlightens the heart and clarifies the mind. "It is the God who said, 'Let light shine out of darkness', who has shone in our hearts to give the light of the knowledge of the glory of God on the face of Christ" (2 Cor 4:6). That is why the words of Jesus explaining his identity and his mission are so important: "I am the light of the world; whoever follows me will not walk in darkness, but will have the light of life" (Jn 8:12).
Our personal encounter with Christ bathes life in new light, sets us on the right path, and sends us out to be his witnesses. This new way of looking at the world and at people, which comes to us from him, leads us more deeply into the mystery of faith, which is not just a collection of theoretical assertions to be accepted and approved by the mind, but an experience to be had, a truth to be lived, the salt and light of all reality (cf. Veritatis Splendor, 88).
In this secularized age, when many of our contemporaries think and act as if God did not exist or are attracted to irrational forms of religion, it is you, dear young people, who must show that faith is a personal decision which involves your whole life. Let the Gospel be the measure and guide of life's decisions and plans! Then you will be missionaries in all that you do and say, and wherever you work and live you will be signs of God's love, credible witnesses to the loving presence of Jesus Christ. Never forget: "No one lights a lamp and then puts it under a bushel" (Mt 5:15)!