From: Luke 10:25-37
Parable of the Good Samaritan
 And behold, a lawyer stood up to put Him (Jesus) to the test, saying, "Teacher, what shall I do to inherit eternal life?"  He said to him, "What is written in the law? How do you read?"  And he answered, "You shall love the Lord your God with all your heart, and with all your soul, and with all your strength, and with all your mind: and your neighbor as yourself."  And He said to him, "You have answered right; do this, and you will live."  But he, desiring to justify himself, said to Jesus, "And who is my neighbor?"  Jesus replied, "A man was going down from Jerusalem to Jericho, and he fell among robbers, who stripped him and beat him, and departed, leaving him half dead.  Now by chance a priest was going down that road; and when he saw him he passed by on the other side.  So likewise a Levite, when he came to the place and saw him, passed by on the other side.  But a Samaritan, as he journeyed, came to where he was; and when he saw him, he had compassion,  and went to him and bound up his wounds, pouring on oil and wine; then he set him on his own beast and brought him to an inn, and took care of him.  And the next day he took out two denarii and gave them to the innkeeper, saying, "Take care of him; and whatever more you spend, I will repay you when I come back.'  Which of these three, do you think, proved neighbor to the man who fell among the robbers?"  He said, "The one who showed mercy on him." And Jesus said to him, "Go and do likewise."
25-28. Our Lord's teaching is that the way to attain eternal life is through faithful fulfillment of the Law of God. The Ten Commandments, which God gave Moses on Mount Sinai (Exodus 20:1-17), express the natural law in a clear and concrete way. It is part of Christian teaching that the natural law exists, that it is a participation by rational creatures in the Eternal Law and that it is impressed on the conscience of every man when he is created by God (cf. Leo XIII, "Libertas Praestantissimum"). Obviously, therefore, the natural law, expressed in the Ten Commandments, cannot change or become outdated, for it is not dependent on man's will or on changing circumstances.
In this passage, Jesus praises and accepts the summary of the Law given by the Jewish scribe. This reply, taken from Deuteronomy (6:4ff), was a prayer which the Jews used to say frequently. Our Lord gives the very same reply when He is asked which is the principal commandment of the Law and concludes His answer by saying, "On these two commandments depend all the law and the prophets" (Matthew 22:40; cf. also Romans 13:8-9; Galatians 5:14).
There is a hierarchy and order in these two commandments constituting the double precept of charity: before everything and above everything comes loving God in Himself; in the second place, and as a consequence of the first commandment, comes loving one's neighbor, for God explicitly requires us to do so (1 John 4:21; cf. notes on Matthew 22:34-40 and 22:37-38).
This passage of the Gospel also included another basic doctrine: the Law of God is not something negative--"Do not do this"--but something completely positive--love. Holiness, to which all baptized people are called, does not consist in not sinning, but in loving, in doing positive things, in bearing fruit in the form of love of God. When our Lord describes for us the Last Judgment He stresses this positive aspect of the Law of God (Matthew 25:31-46). The reward of eternal life will be given to those who do good.
27. "Yes, our only occupation here on earth is that of loving God--that is, to start doing what we will be doing for all eternity. Why must we love God? Well, because our happiness consists in love of God; it can consist in nothing else. So, if we do not love God, we will always be unhappy; and if we wish to enjoy any consolation and relief in our pains, we will attain it only by recourse to love of God. If you want to be convinced of this, go and find the happiest man according to the world; if he does not love God, you will find that in fact he is an unhappy man. And, on the contrary, if you discover the man most unhappy in the eyes of the world, you will see that because he loves God he is happy in every way. Oh my God!, open the eyes of our souls, and we will seek our happiness where we truly can find it" (St. John Mary Vianney, "Selected Sermons", Twenty-second Sunday after Pentecost).
29-37. In this moving parable, which only St. Luke gives us, our Lord explains very graphically who our neighbor is and how we should show charity towards him, even if he is our enemy.
Following other Fathers, St. Augustine ("De Verbis Domini Sermones", 37) identifies the Good Samaritan with our Lord, and the waylaid man with Adam, the source and symbol of all fallen mankind. Moved by compassion and piety, He comes down to earth to cure man's wounds, making them His own (Isaiah 53:4; Matthew 8:17; 1 Peter 2:24; 1 John 3:5). In fact, we often see Jesus being moved by man's suffering (cf. Matthew 9:36; Mark 1:41; Luke 7:13). And St. John says: "In this the love of God was made manifest among us, that God sent His only Son into the world so that we might live through Him. In this is love, not that we loved God but that He loved us and sent His Son to be the expiation for our sins. Beloved, if God so loved us, we also ought to love one another" (1 John 4:9-11).
This parable leaves no doubt about who our neighbor is--anyone (without distinction of race or relationship) who needs our help; nor about how we should love him--by taking pity on him, being compassionate towards his spiritual and corporal needs; and it is not just a matter of having the right feelings towards him; we must do something, we must generously serve him.
Christians, who are disciples of Christ, should share His love and compassion, never distancing themselves from others' needs. One way to express love for one's neighbor is perform the "works of mercy", which get their name from the fact that they are not duties in justice. There are fourteen such works, seven spiritual and seven corporal. The spiritual are: To convert the sinner; To instruct the ignorant; To counsel the doubtful; To comfort the sorrowful; To bear wrongs patiently; To forgive injuries; To pray for the living and the dead. The corporal works are: To feed the hungry; To give drink to the thirsty; To clothe the naked; To shelter the homeless; To visit the sick; To visit the imprisoned; To bury the dead.
31-32. Very probably one reason why our Lord used this parable was to correct one of the excesses of false piety common among His contemporaries. According to the Law of Moses, contact with dead bodies involved legal impurity, from which one was cleansed by various ablutions (cf. Numbers 19:11-22; Leviticus 21:1-4, 11-12). These regulations were not meant to prevent people from helping the injured; they were designed for reasons of hygiene and respect for the dead. The aberration of the priest and the Levite in this parable consisted in this: they did not know for sure whether the man who had been assaulted was dead or not, and they preferred to apply a wrong interpretation of a secondary, ritualistic precept of the Law rather than obey the more important commandment of loving one's neighbor and giving him whatever help one can.
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.