Pope Saint Leo the Great

This marvel of the transfiguration contains another lesson for the apostles, to strengthen them and lead them into the fullness of knowledge. Moses and Elijah, the law and the prophets, appeared with the Lord in conversation with him. This was in order to fulfil exactly, through the presence of these five men, the text which says: Before two or three witnesses every word is ratified. What word could be more firmly established, more securely based, than the word which is proclaimed by the trumpets of both old and new testaments, sounding in harmony, and by the utterances of ancient prophecy and the teaching of the Gospel, in full agreement with each other?

The writings of the two testaments support each other. The radiance of the transfiguration reveals clearly and unmistakably the one who had been promised by signs foretelling him under the veils of mystery. As Saint John says: The law was given through Moses, grace and truth came through Jesus Christ. In him the promise made through the shadows of prophecy stands revealed, along with the full meaning of the precepts of the law. He is the one who teaches the truth of the prophecy through his presence, and makes obedience to the commandments possible through grace.

In the preaching of the holy Gospel all should receive a strengthening of their faith. No one should be ashamed of the cross of Christ, through which the world has been redeemed.

-- Pope Saint Leo the Great from a homily on The Transfiguration

Saint Louis de Montfort

The Our Father contains all the duties we owe to God, the acts of all the virtues and the petitions for all our spiritual and corporal needs.

-- Saint Louis de Montfort

Saint John Mary Vianney

Prayer is nothing else but union with God. In this intimate union, God and the soul are fused together like two bits of wax that no one can ever pull apart. This union of God with a tiny creature is a lovely thing. It is a happiness beyond understanding. 

-- Saint John Mary Vianney

Pope Saint Gregory the Great

As for certain lesser faults, we must believe that, before the Final Judgment, there is a purifying fire. He who is truth says that whoever utters blasphemy against the Holy Spirit will be pardoned neither in this age nor in the age to come. From this sentence we understand that certain offenses can be forgiven in this age, but certain others in the age to come.

-- Pope Saint Gregory the Great

Saint Peter Julian Eymund

If the love of Jesus in the Most Blessed Sacrament does not win our hearts, Jesus is vanquished! Our ingratitude is greater than His Goodness our malice is more powerful than His Charity. 

-- Saint Peter Julian Eymund 

Saint Alphonsus Liguori

When we hear people talk of riches, honors and amusements of the world, let us remember that all things have an end, and let us then say: "My God, I wish for You alone and nothing more." 

-- Saint Alphonsus Liguori

Saint Ignatius of Loyola

Do not let any occasion of gaining merit pass without taking care to draw some spiritual profit from it; as, for example, from a sharp word which someone may say to you; from an act of obedience imposed against your will; from an opportunity which may occur to humble yourself, or to practice charity, sweetness, and patience. All of these occasions are gain for you, and you should seek to procure them; and at the close of that day, when the greatest number of them have come to you, you should go to rest most cheerful and pleased, as the merchant does on the day when he had had most chance for making money; for on that day business has prospered with him. 

-- Saint Ignatius of  Loyola