The Good Samaritan who renders help is the Savior Jesus. He is a "layman" of low estate. He is despised and slandered as an outcast and reject. Yet His human morality is of the highest order.
The Jews called him a Samaritan with a demon to utterly insult and reject Christ
(John 8:48). But He is the highest moral MAN who has ever lived. He is able to help the self-righteous and self-justifying one who is on his way down to God's place of a curse.
Jesus came down as the most proper Man and had compassion on us. In tenderness He sought to save sinners who are blindly self-righteous yet torn up and robbed by the religion which cannot heal them.
"But a certain Samaritan, who was journeying, came upon him; and when he saw him, he was moved with compassion; And he came to him and bound up his wounds and poured oil and wine on them. And placing him on his own beast, he brought him to an inn and took care of him."
The pouring on the wounds with the oil signifies the dispensing of the Holy Spirit to the forgiven and healed sinner. Christ in saving imparts the Spirit of God to regenerate and heal the self righteous self justifying victim of legalism.
In short Christ brings the sinner to the new covenant church where He leaves him to be taken care of until the time of His second coming. Then in the time of His second coming He will recompense His faithful servants who also have compassion and care for those whom Jesus has brought into the church - the "inn".
"And on the next day he took out two denarii and gave them to the innkeeper and said, Take care of him; and whatever you spend in addition to this; when I return I will repay you."
This is not the repaying of a man with the GIFT of eternal life. This is the recompensing of His servants with some reward in the millennial kingdom in addition, for their compassion and faithfulness in being like the Lord Jesus.
The innkeeper points to those who shepherd the new covenant church all during the church age caring for the believers who are brought there by the Savior Jesus. Actually, they call came into the church in a similar way.
The self justifying lawyer needed a man like this with great compassion and the ability to help him by being His good neighbor.