Just as water vapour created from the ocean, turns to clouds, falls as rain, becomes a river and finally returns back to the ocean, our soul having been created by God will finally return to God's being. This is the cycle of our soul body and its final destiny.
The evolution of our soul is the evolution of our awareness. When our soul was created it existed in the Heavens in a very simple state of consciousness with very little awareness of itself. Just like a fish in a school of fish has very little awareness of itself and follows its school wherever the school goes.
From the Heavens the soul is then is thrust into its sojourn of incarnations on earth where it faces the challenges of living in a dense physical body and the mind with their intense impulses and strong tendencies for attachments. As the soul lives from life to life, it slowly gains mastery over the body and mind. The soul's individual awareness is thus developed from its simple beginnings.
According to the enlightened masters, without living on earth with the physical body the soul’s awareness cannot develop. The spiritual development of the soul ultimately leads to the realization of our innate Oneness with God within the core of our soul.
When our soul, or rather when we are firmly grounded in God consciousness through these realizations we will attain freedom from rebirth on earth or moksha. After moksha we continue to live in the heavens in our soul body for many more eons until we finally merge back into God Almighty from whence we came.
This is the destiny of all souls, no matter what ones religion or beliefs may be. When the time is opportune according to our karma and by the Grace of God, the primordial stirrings of our soul will motivate us to seek God within ourselves in the quest to know the truths of God and life. This will inevitably happen to all souls in one life on earth or another.