The purpose of a Soul's Earth lives and sojourns in between is self-improvement leading to Nirvana and Enlightenment, hence the parable of The Prodigal Son, but there is often also a mission - perhaps more obvious in some than in others - and an example of this is a doctor who made it his life's mission to provide, or cause to be provided, much needed opthalmic care to the poor in many parts of the world. On the other hand part of his purpose would have been to learn to curb his abrasive manner.