One commentary notes:
Probably no parable has been allegorized more often than this one. The
most famous allegory is that of Augustine.49 The irony of Augustine’s
and similar allegorical interpretations is that the parable is
introduced (10:29) and concludes with (10:36) questions about what it
means to be a neighbor, whereas the allegorical interpretations do not
deal with this issue at all. Clearly, Luke’s main point in retelling
the parable must have been what it means to be a neighbor. Jesus and
Luke sought to illustrate that the love of one’s neighbor must
transcend all natural or human boundaries such as race, nationality,
religion, and economic or educational status.[Stein, R. H. (1992).
Luke (Vol. 24, pp. 318–319). Nashville: Broadman & Holman Publishers.]
Parable's are not allagories of salvation, though some may be teaching soteriological themes and as such they might have characters in them who can be directly equated to the Lord Jesus Christ. That is to say we shouldn't always be looking to find Jesus in that direct fashion in every parable.
Furthermore contrary to the opinions of some, one cannot read any hostility towards the Samaritans in Jesus' character. It is reading a lot into Matt 10:5 to assume that means that Jesus is hostile to Samaritans, especially when we consider other things that Jesus does and says, for example:
1) We have the incident with the Samaritan women in John and
2) We also have his instruction to the same disciples in Acts 1:8 to go to Samaria.
Furthermore, in this writers opinion, it is exegetically untenable to link Matt 10:5 with the parable of the good Samaritan1.
However returning to the parable of the good Samaritan it is important to understand the context of what is being said.
A 'lawyer' has come to Jesus with a question about how to inherit eternal life (v25) and Jesus has responded with a question of his own (v26) the lawyer responds by reciting Deut 6:8 and Leviticus 19:18 and Jesus agrees with him and tells him to do those things, the men then asks, 'who is my neighbour' (v29) and Jesus answers that question with the parable.
In the Parable a man (presumably Jewish) is set upon and left for dead. Two respected men who have positions of responsibility in society and who might be expected to offer some aid ignore the man's plight however another man, who is a Samaritan does stop and does help the man.
What is remarkable about this story is that if the roles were reversed it is incredibly unliekly that the Jewish man would help him, and he probably knows that but he doesn't care. Rather he sees a man in need and he goes out of his way (at some personal expense) to help that men.
After telling the story Jesus then asks the lawyer another question.
"So which of these three do you think was neighbor to him who fell
among the thieves?" (Luk 10:36 NKJ)
To which the man replies:
"He who showed mercy on him." (Luk 10:37 NKJ)
Then we read:
Then Jesus said to him, "Go and do likewise." (Luk 10:37 NKJ)
The good Samaritan is a fictional character, however the direct application of what Jesus is saying is that if this lawyer wants to gain eternal life through his own efforts this is what he will have to be like.
See for example:
All that remains is that men should put this into effect. With
authority Jesus commands the lawyer to go away and begin to follow the
Samaritan’s example; the command in v. 28 cannot be evaded.[Marshall,
I. H. (1978). The Gospel of Luke: a commentary on the Greek text (p.
450). Exeter: Paternoster Press.]
Now, in regards to the Lord Jesus Christ one might go from the parable to the character of Jesus and find many parallels between him and the good Samaritan in the light of such passages as Phil 2:5-9 but that is not the same as saying Jesus was speaking about himself, he wasn't, he was speaking about the lawyer.
1 The only reason this writer can see to link the two passages together is in an effort to set scripture against scripture for the purpose of showing contradictions or errors.