The story of the Good Samaritan reads like a parable, but there is no indication that it couldn't be historical. With that in mind, let us treat it as something Christ fulfills in each of us. Do you see yourself in the characters? You should, for we indeed are each, though this be uncomfortable to think about.
The lawyer excluded certain people from his definition of "neighbor." Who is yours? Are you self-righteous, like he was? All people should be your neighbor, as described by the Leviticus text - it is moral (versus ceremonial) law, i.e. how to treat those around us.
"Love your neighbor." We need someone to love us. Like the man foolishly walking through a dangerous area, we cannot take care of ourselves spiritually and morally in today's culture; we need help and helpers.
We DO have such a Neighbor! He has given of Himself to rescue the half-dead, us unworthy sinners! The innkeepers are pastors, stewards of His gifts. Christ is here, among us, to pay for, heal, and give of Himself to us! Therefore we are forgiven of sins, and given Christ. Fulfill the parable by loving your neighbor as you have been loved.
Soli Deo gloria.