Since I'm at work I don't have access to my actual Bible study tools, but the Parable of the Good Samaritan is specifically discussing a Samaritan helping someone who was beaten and left on the side of the road.

First, it's important to note that Jesus was talking to a Jewish crowd (according to the narrative). And now, breaking down the narrative we see that this man was beaten and left on the side of the road. He was then passed by a priest and a Levite. Both are people the audience would expect to help a beaten, and stripped man. However, it was the Samaritan who helped him.

What's important here is that Samaritans and Jews did not get along at the time of the narrative (in fact, relations are still not the greatest). So, to the audience, this was a big surprise that a Samaritan would go out of his way, whereas two prominent Jewish people would not.

In the context of the Bible, this was Jesus's response to the question "Who is my neighbor?" In Luke 10: 25-29:

25 On one occasion an expert in the law stood up to test Jesus. “Teacher,” he asked, “what must I do to inherit eternal life?”

26 “What is written in the Law?” he replied. “How do you read it?”

27 He answered, “‘Love the Lord your God with all your heart and with all your soul and with all your strength and with all your mind’[c]; and, ‘Love your neighbor as yourself.’[d]”

28 “You have answered correctly,” Jesus replied. “Do this and you will live.”

29 But he wanted to justify himself, so he asked Jesus, “And who is my neighbor?”

After the parable, verses 36-37:

36 “Which of these three do you think was a neighbor to the man who fell into the hands of robbers?”

37 The expert in the law replied, “The one who had mercy on him.”

Jesus told him, “Go and do likewise.”

The point is that your neighbor isn't just someone you would want to be your neighbor, but those who you may not expect to be your neighbor. Using a Samaritan was just a good way to illustrate that to the audience.

If requested I can provide some sources for stuff when I get home from work.

The parable of the Good Samaritan is a rather misunderstood passage from the Gospels. Samaritans were people who shared the same sacred text as the Jewish people, but they were not Jews. In essence, they were foreigners, they were "others". So the distinction in the parable is not really between people who do good deeds and people who do not. It is between those who are supposed to be "good" and worthy of eternal life because they are strict followers of the Jewish law, and those who are not even Jews and not bound by the requirements of the law. So to answer the question posed to him, "What shall I do to inherit eternal life?", Jesus makes the theological point that the law should be interpreted in a way that does not make those who follow it strictly as morally superiors to "others" who do good deeds.