a Samaritan: This unexpected change in the story probably surprised the listeners. Jews and Samaritans hated each other (see 9:52–53; 17:16; John 4:4–42). After Assyria conquered the northern kingdom of Israel, Assyrian settlers married Israelites who remained in Samaria. Their descendants became known as Samaritans.
Later, after the Judeans returned from Babylon, conflict grew between Jews and Samaritans (Ezra 4:1–24). The Samaritans built their own temple on Mount Gerizim. They also used their own version of the Pentateuch, the first five books of the Bible, as Scripture.
This hatred grew worse when the Jewish king John Hyrcanus attacked the Samaritans and destroyed their temple on Mount Gerizim. This happened around 128 BC. Because of this long hatred, no first-century Jew would expect a despised Samaritan to help a wounded Jew. But in God’s kingdom, a despised foreigner becomes a true neighbor who helps!