The Solemnity of the Transfiguration probably arose from the annual commemoration of the dedication of a Basilica of the Transfiguration on Mount Tabor. In the ninth century the feast spread to the West and later, during the eleventh and twelfth centuries, it started to be celebrated also in Rome, in the Vatican Basilica. Pope Callistus III incorporated the feast into the Roman Calendar in 1457, in gratitude for the victory of the Christian armies against the Turks in the Battle of Belgrade on 6 August 1456.
In the Christian East the Transfiguration of our God and Saviour Jesus Christ is one of the greatest solemnities of the year, together with Easter, Christmas and the Exaltation of the Holy Cross. It expresses all the theology of divinization through grace by which human nature, clothed in Christ, is illuminated with the splendour of God’s glory. If we are united to Jesus, as the office of readings in the Roman rite tells us, he “will give us a share in his radiance, renew our spiritual nature and transform us into his own likeness, making us for ever sharers in his Godhead.”
With Peter, James and John, in this feast we are invited to make Jesus the focus of our attention: This is my beloved Son, with whom I am well pleased; listen to him (Mt 17:5). We have to listen to him and let his life and teachings make our ordinary lives divine. Saint Josemaria prayed: “Lord, we are ready to heed whatever you want to tell us. Speak to us: we are attentive to your voice. May your words enkindle our will so that we launch out fervently to obey you.”
Listening to our Lord with the sincere desire to identify ourselves with him leads us to accept sacrifice. Jesus was transfigured so that the scandal of the Cross might be removed from the hearts of his disciples, to help them bear the dark moments of his Passion. The Cross and glory are closely united. The forty days between the feast of the Transfiguration, 6 August, and the Exaltation of the Holy Cross, form in some traditions a second Lent. Hence in the Byzantine tradition this period is observed as a time for fasting and contemplation of the Cross.
José Luis Gutiérrez
 Anastasius of Sinai, Sermon on the Transfiguration of the Lord. Liturgy of the Hours, Office of Readings for 6 August.
 Saint Josemaria, Holy Rosary, Fourth Luminous Mystery.
 Roman Missal, Preface for the feast of the Transfiguration.
Texts from Saint Josemaria:
And he was transfigured before them, and his face shone like the sun, and his garments became white as light (Mt 17:2). Jesus, we want to see you, to speak to you! We want to contemplate you, immersed in the immensity of your beauty, in a contemplation that will never cease! It must be wonderful to see you, Jesus! It must be wonderful to see you and be wounded by your love!
And a voice from the cloud said, This is my beloved Son, with whom I am well pleased; listen to him (Mt 17:5). Lord, we are ready to heed whatever you want to tell us. Speak to us: we are attentive to your voice. May your words enkindle our will so that we launch out fervently to obey you.
Vultum tuum, Domine, requiram (Ps 26:8). Lord, I long to see your face. I like to close my eyes and think that, when God wills, the moment will come when I will be able to see him, not as in a mirror dimly, but …face to face (1 Cor 13:12). Yes, my heart yearns for God, the living God. When shall I go and behold the face of God?
Holy Rosary, Fourth Luminous Mystery
Our being children of God, I insist, leads us to have a contemplative spirit in the midst of all human activities; to be light, salt and leaven through our prayer, through our mortification, through our knowledge of religion and of our profession. We will carry out this aim: the more within the world we are, the more we must be God's.
The Forge, 740
Rest assured that it is not difficult to convert work into a prayerful dialogue. As soon as you offer it up and then set to work, God is already listening and giving encouragement. We acquire the style of contemplative souls, in the midst of our daily work! Because we become certain that he is watching us, while he asks us to conquer ourselves anew: a little sacrifice here, a smile there for someone who bothers us, beginning the least pleasant but most urgent job first, carefulness in little details of order, perseverance in the fulfillment of our duty when it would be so easy to abandon it, not leaving for tomorrow what should be finished today: and all this, to please him, our Father God! On your desk or in some inconspicuous place that nobody notices, you perhaps place your crucifix to awaken in you a contemplative spirit and to act as a textbook for your mind and soul where you learn the lessons of service.
If you make up your mind to follow these ways of contemplation, in the midst of your ordinary work, without doing anything odd or withdrawing from the world, you will immediately feel that you are a friend of the Master, with the God-given task of opening up the divine ways of the earth to the whole of mankind. Yes. With your work you will help to spread Christ’s kingdom in every continent. You will offer up hour after hour of work for far-off lands which are being born to the faith, for the peoples of the East who are being cruelly forbidden to profess their faith, and for the traditionally Christian nations where it seems that the light of the Gospel has grown dim and souls are struggling in the obscurity of ignorance... Then, how valuable your hour of work becomes as you persevere with the same effort a little longer, a few minutes more, until the job is finished! In a simple and practical way you are converting contemplation into apostolate, seeing it as an imperative necessity of your heart, which beats in unison with the most sweet and merciful Heart of Jesus, Our Lord.
Friends of God, 67