The spiritual purpose of ego
Ego — the part of the mind that mediates between the conscious and the unconscious and is responsible for reality testing and a sense of personal identity. (New Oxford American Dictionary).
Ego develops as language develops. It could be assumed that ego is an invented concept (as is language and time) that floats on the surface of life. Using the metaphor of a pond: ego is the surface that is readily seen and experienced and the spiritual self or Being is all the water seen and unseen. Being is largely unknown for a variety of reasons one of which is we come to believe we are ego and get attached the content of our lives. We miss the context of our lives which belongs with Being or a kind of spiritual gestalt.
Most religious and/or spiritual precepts define our spiritual selves in a wide variety of ways. The spiritual is universal and transcends ego to include greater consciousness. Ego is relegated to describe the spiritual, which is often ineffable.
…the ego must be destroyed to let the Spirit side of us flourish. This, of course, is impossible.
The spiritual side of our nature is often left fallow and underdeveloped because our attention is outward in the world of stuff, things and the temporary desires of ego. Meditation and other spiritual practices allow us to look inward, connect with our spirit and create a ground for our Being self to grow and mature.
Many secular people think that the ego must be destroyed to let the Spirit side of us flourish. This is impossible. Ego is so intertwined with our lives with language, with linear time, with relationships that it becomes seamless and invisible unless we reflect upon it. Once ensconced by ego development and inculcated within its matrix even reflection does not supply an adequate release from its trappings. Illusion is created by ego in thinking that ego is egoism and can be eradicated. We need ego to interface with the politically social world with its rules and meta-rules, and manage the mundane of our lives.
The friction created between Spirit/Being and ego can be used to create energy.
From the point of view of a developed Spiritual Self/Being the ego provides conditions of human existence — or lessons that define the parameters/conditions of having a body and being in a human society. There will always be lessons as long as we dwell in a physical body. This is the good news.
When we accept that the ego will always be there and we develop an ego that has integrity then the work between our Spiritual nature and ego can begin. The friction created between Spirit and ego can be used to create energy that may be expended or saved for future Being/Spiritual work. This could be called the work of consciousness and transcendence of ego while under the conditions of our physical bodies. Part of the purpose of the human experience is utilizing the energy of attachment (especially the attachments to suffering*) to release it moment by moment and transcend into a higher level of consciousness.
This higher level of consciousness (will always be claimed by ego) allows for perceiving unseen worlds that bind all spirits chained in biological and non-biological forms. This binding helps our egos to experience love and compassion which is the light that permeates all substances and is the beginning of enlightenment.
* even avoiding suffering is an attachment to suffering because it is a response to a dislike. By releasing attachments to pain, for instance, some of the pain can be released.