The parable we have heard today is called the Parable of the Good Samaritan. However, the Lord Jesus simply called the man "a certain Samaritan." Christ also taught us, "So likewise ye, when ye shall have done all those things which are commanded you, say, We are unprofitable servants: we have done that which was our duty to do." (Luke 17:10) The Lord did not, therefore, assign the title "good" to the Samaritan for doing what was, in the story, simply the man's duty to his neighbor as revealed in the Law of God. The Samaritan is not held up as an extraordinary example, but merely as a proper example. If there is anything praiseworthy about the Samaritan, it is his mercy and humility. For, the Samaritan was chosen to be an exemplary character in the story, quite deliberately, to make a simple point: You must love your neighbor without regard for how he has treated you, or how you expect him to treat you later.
And, concerning that Law, the second great commandment is this: Thou shalt love thy neighbor as thyself. Jesus has taught us the way, and in showing us the way has redeemed us from sin and death on his cross.