Definition of "SOUL."
Ray Charles.
There's isn't another entertainer that can sing with feeling like Ray and also play his instrument with the same feeling (for Ray the piano) that I've ever heard.

Since the beginning of time he'd be the musician I'd kill for to jam with.
He knew his stuff. Everyone one else can only come in second to Ray. Guitar strummers don't count.

I'm talking musicians who can get up and improvise with any commercial band on any commercial tune. Ray could cut it friends.