All souls have a singular, common goal. Namely, to develop their myriad spiritual attributes to the point of divine perfection. It is through the process of repeated incarnations in mortal hosts (vehicles of expression) on the physical plane that they endeavor to accomplish this feat.
Initially, all souls shared a common degree of the spiritual power, knowledge and wisdom of the original godhead from whence they sprang forth at the point of so-called 'creation.'
The degree to which each originally possessed such attributes was directly proportional to the number of the parts that were divinely willed into being by the whole of those same parts or God.
With each successive incarnation on this plane, a soul gains increased development of one or more spiritual attributes by virtue of that incarnation's life experience. Physical reality is to an individual soul what a barbell is to a weightlifter. That is, the resistance against which repetition leads to mastery.
The muscles of a weightlifter become stronger, the more weight he lifts and more often he lifts it. By the same token, with each reincarnation a soul becomes better able to impress its all-loving will, motivation and guidance upon the physical mind of its mortal host on this plane. In each case, development is the goal. Resistance is the means by which it is achieved.
Each soul looks forward with eager anticipation to the time it will have evolved its many divine spiritual attributes via reincarnation to the point it can shed the need for that process altogether. Although there is no spiritual necessity for further earthly incarnations at that point, a given soul can choose to continue the process anyway. A great many do so. They do so in order to
reach out to less-evolved incarnate souls through their own flesh vehicles and help those souls evolve more fully in a given earth life than they would otherwise do.