From: Luke 11:1-4
The Our Father
 He (Jesus) was praying in a certain place, and when He ceased, one of His disciples said to Him, "Lord, teach us to pray, as John taught His disciples."  And He said to them, "When you pray, say: `Our Father, hallowed be Thy name. Thy Kingdom come.  Give us each day our daily bread;  and forgive us our sins, for we ourselves forgive every one who is indebted to us; and lead us not into temptation.'"
1-4. St. Luke gives us a shorter form of the Lord's Prayer, or Our Father, than St. Matthew (6:9-13). In Matthew there are seven petitions, in Luke only four. Moreover, St. Matthew's version is given in the context of the Sermon on the Mount and specifically as part of Jesus' teaching on how to pray; St. Luke's is set in one of those occasions just after our Lord has been at prayer--two different contexts. There is nothing surprising about our Lord teaching the same thing on different occasions, not always using exactly the same words, not always at the same length, but always stressing the same basic points. Naturally, the Church uses the longer form of the Lord's Prayer, that of St. Matthew.
"When the disciples asked the Lord Jesus, `Teach us to pray', He replied by saying the words of the `Our Father', thereby giving a concrete model which is also a universal model. In fact, everything that can and must be said to the Father is contained in those seven requests which we all know by heart. There is such simplicity in them that even a child can learn them, but at the same time such depth that a whole life can be spent meditating on their meaning. Isn't that so? Does not each of those petitions deal with something essential to our life, directing it totally towards God the Father? Doesn't this prayer speak to us about `our daily bread', `forgiveness of our sins, since we forgive others' and about protecting us from `temptation' and `delivering us from evil?'" ([Pope] John Paul II, "General Audience", 14 March 1979).
The first thing our Lord teaches us to ask for is the glorification of God and the coming of His Kingdom. That is what is really important--the Kingdom of God and His justice (cf. Matthew 6:33). Our Lord also wants us to pray confident that our Father will look after our material needs, for "your Heavenly Father knows that you need them all" (Matthew 6:32). However, the Our Father makes us aspire especially to possess the goods of the Holy Spirit, and invites us to seek forgiveness (and to forgive others) and to avoid the danger of sinning. Finally the Our Father emphasizes the importance of vocal prayer. "`Domine, doce nos orare. Lord teach us to pray!' And our Lord replied: `When you pray say: "Pater noster, qui es in coelis"... Our Father, who art in Heaven...'. What importance we must attach to vocal prayer!" ([St] J. Escriva, "The Way", 84).
1. Jesus often went away to pray (cf. Luke 6:12; 22:39ff). This practice of the Master causes His disciples to want to learn how to pray. Jesus teaches them to do what He Himself does. Thus, when our Lord prays, He begins with the Word "Father!": "Father, into Thy hands I commit My spirit" (Luke 23:46); see also Matthew 11:25; 26:42, 53; Luke 23:34; John 11:41; etc.). His prayer on the Cross, "My God, My God,..." (Matthew 27:46), is not really an exception to this rule, because there He is quoting Psalm 22, the desperate prayer of the persecuted just man.
Therefore, we can say that the first characteristic prayer should have is the simplicity of a son speaking to his Father. "You write: `To pray is to talk with God. But about what?' About what? About Him, about yourself: joys, sorrows, successes, failures, noble ambitions, daily worries, weaknesses! And acts of thanksgiving and petition: and love and reparation. In a word: to get to know Him and to get to know yourself: `to get acquainted!'" ([St] J. Escriva, "The Way", 91).
2. "Hallowed be Thy name": in this first petition of the Our Father "we pray that God may be known, loved, honored and served by everyone and by ourselves in particular." This means that we want "unbelievers to come to a knowledge of the true God, heretics to recognize their errors, schismatics to return to the unity of the Church, sinners to be converted and the righteous to persevere in doing good." By this first petition, our Lord is teaching us that `we must desire God's glory more than our own interest and advantage." This hallowing of God's name is attained "by prayer and good example and by directing all our thoughts, affections and actions towards Him" ("St. Pius X Catechism", 290-293).
"Thy Kingdom come": "By the Kingdom of God we understand a triple spiritual kingdom--the Kingdom of God in us, which is grace; the Kingdom of God on earth, which is the Catholic Church; and the Kingdom of God in Heaven, which is eternal bliss [...]. As regards grace, we pray that God reign in us with His sanctifying grace, by which He is pleased to dwell in us as a king in his throne-room, and that He keeps us united to Him by the virtues of faith, hope and charity, by which He reigns in our intellect, in our heart and in our will [...]. As regards the Church, we pray that it extend and spread all over the world for the salvation of men [...]. As regards Heaven, we pray that one day we be admitted to that eternal bliss for which we have been created, where we will be totally happy" ("ibid.", 294-297).
3. The Tradition of the Church usually interprets the "bread" as not only material bread, since "man does not live by bread alone, but by every word that proceeds from the mouth of God" (Matthew 4:4; Deuteronomy 8:3). Here Jesus wants us to ask God for "what we need each day for soul and body [...]. For our soul we ask God to sustain our spiritual life, that is, we beg Him to give us His grace, of which we are continually in need [...]. The life of our soul is sustained mainly by the divine word and by the Blessed Sacrament of the Altar [...]. For our bodies we pray for what is needed to maintain us" ("St. Pius X Catechism", 302-305).
Christian doctrine stresses two ideas in this petition of the Our Father: the first is trust in Divine Providence, which frees us from excessive desire to accumulate possessions to insure us against the future (cf. Luke 12:16-21); the other idea is that we should take a brotherly interest in other people's needs, thereby moderating our selfish tendencies.
4. "So rigorously does God exact from us forgetfulness of injuries and mutual affection and love, that He rejects and despises the gifts and sacrifices of those who are not reconciled to one another" ("St. Pius V Catechism", IV, 14, 16).
"This sisters, is something which we should consider carefully; it is such a serious and important matter that God should pardon us our sins, which have merited eternal fire, that we must pardon all trifling things which have been done to us. As I have so few, Lord, even of these trifling things, to offer Thee, Thy pardoning of me must be a free gift: there is abundant scope here for Thy mercy. Blessed be Thou, who endurest one that is so poor" (St. Teresa of Avila, "Way of Perfection", Chapter 36).
"And lead us not into temptation": it is not a sin to "feel" temptation but to "consent" to temptation. It is also a sin to put oneself voluntarily into a situation which can easily lead one to sin. God allows us to be tempted, in order to test our fidelity, to exercise us in virtue and to increase our merits with the help of grace. In this petition we ask the Lord to give us His grace not to be overcome when put to the test, or to free us from temptation if we cannot cope with it.
Source: "The Navarre Bible: Text and Commentaries". Biblical text taken from the Revised Standard Version and New Vulgate. Commentaries made by members of the Faculty of Theology of the University of Navarre, Spain. Published by Four Courts Press, Kill Lane, Blackrock, Co. Dublin, Ireland. Reprinted with permission from Four Courts Press and Scepter Publishers, the U.S. publisher.