The prodigal son has been claimed oftentimes to represent the repentant soul, this makes its identity clear. I believe there is more to the story. The father said all things belong to the first child who has always been obedient to him. Who is the first child?
I wouldn't agree it's Jesus since he can't in any way be envious of people. It is related that the first child was envious when the father killed the fattest cow for the returned son. Who does he symbolize?