From a letter to Proba by Saint Augustine, bishop
If you study every word of the petitions of Scripture, you will find, I think, nothing that is not contained and included in the Lord’s Prayer. When we pray, then, we may use different words to say the same things, but we may not say different things.
We should not hesitate to make these prayers for ourselves, for our friends, for strangers, and even for enemies, though the emotions in our heart may vary with the strength or weakness of our relationships with individuals.
You now know, I think, the attitudes you should bring to prayer, as well as the petitions you should make, and this not because of what I have taught you but thanks to the teaching of the one who has been pleased to teach us all.
We must search out the life of happiness, we must ask for it from the Lord our God. Many have discussed at great length the meaning of happiness, but surely we do not need to go to them and their long drawn out discussions. Holy Scripture says concisely and with truth: Happy is the people whose God is the Lord. We are meant to belong to that people, and to be able to see God and live with him forever, and so the object of this command is love from a pure heart, from a good conscience and a sincere faith.
In these three qualities, “a good conscience” stands for “hope.” Faith, hope and love bring safely to God the person who prays, that is, the person who believes, who hopes, who desires, and who ponders what he is asking of the Lord in the Lord’s Prayer.
St. Augustine. 14th C. Cappellone di San Nicola, Basilica di San Nicola da Tolentino, Tolentino, Italy.