The 'Great Quest' that human beings experience at a certain point in their spiritual evolultion is related to the surrender of the lower-self and the desire-nature in favor of a deeper and higher truth .
This truth can be pursued and found in different ways: Through meditation of many different kinds one finds the space of pure Awareness that is more real than the turmoil of the mental and emotional self which claim our attention most of the time. Locating this Space does not involve 'overcoming' the lower self as much as letting it go - separating from the lesser reality in favor of the greater.
By contrast, the 'path of purification' aims to overcome the lower self through surrender of the lower to the higher and the transmutation of the lower, based on love. This fundamentally alchemical process changes the quality and frequency of vibration of the lower self, raising all emotional and mental energies to their higher counterparts. In this sense it transmutes and redeems the personality, divinizing it, removing negative influences through their exposure to and incorporation by spiritual light. In the presence of light, all that is separated and dark becomes aligned with the energy of light and love.
The alchemy of purification is based on the surrender of personal will to a higher Will by whatever name that higher Will is called. The lower ego-self, no longer in charge of what formerly was its own doman, asks to serve the will of the Divine - to become aligned with it in such a way that the healing of all that is not in harmony with love's purposes can take place.
Surrender to God's pure Will is accompanied by efforts on the human level to align with the power of love that emerges through that Will. Such love is the motivating force for Creation, and it becomes the motivating force for the pursuit of return to the Divine as well. The One Spirit that we call God is simultaneously that which we bow to and offer our loving service to, and our own deepest essence. This One does not only rule over life, it exists within life and within each molecule and cell of all that is.
The Great Quest absorbs all lesser quests within itself, not only because it is more difficult but also because it is more comprehensive.
All of human experience is part of this Quest, for we are each on a journey to Truth and Reality, yet much of this journey is not self-aware. However, at some point within that journey the courage develops and the need appears to let go of all illusions about the self, all defense, fears, and obstacles we have placed in our own way, in order to find the greater Reality that we are. Some reach that point earlier in the long arc of spiritual evolution, some later on, but all are on the same trajectory toward truth.
The mystery of the 'Holy Grail of Truth' is that what we seek has always been with us and within us. It is both 'outside' and 'inside', both 'above' and 'below', both invisible and visible. That which we seek is the Divine Being of the All - the Oneness of the One that is in and around all things.
Blessed be those who are willing to undertake the Great Quest, for their victory shall be assured.