“Initiation awakens one to ultimate reality and from then onward one meditates through all the various stages of the Path. Having endeavored to discover the non-selfhood of personality, which is common to all exoteric traditions, one examines the self by means of logic, the teaching, and analogies and, not finding the self, one understands selflessness. One must then bring the mind into a quiet state. When the mind is calmed by means of such reasoning, discriminating thought ceases and mind reaches a non-conceptual state. If one continues in this state for days, months, and years, so oblivious to the passing of time that one needs to be reminded of it by others, one has then achieved tranquility of mind.
“This state of tranquility is maintained by means of continued attention and awareness, not allowing it to become distracted or to sink into passivity. Intensified by the force of awareness, one experiences pure consciousness without differentiation – naked, vivid, and crisp. These are the characteristics of tranquility of mind.
“Pure consciousness may be regarded as a flash of perfect insight; individuals do not actually experience it until they reach the first stage of Enlightenment. At this stage, one meditates, visualizing the forms of the yidam. In so doing one may experience visions and forms, but these are devoid of substance and are merely products of meditation.
“To sum up: First, a vivid state of mental tranquility and a sustaining energy together with a discerning intellect are indispensable requirements for attaining perfect insight. They are like the first steps of a staircase.
“Second, all meditation, with or without form, must begin from deeply aroused compassion and love. Whatever one does must emerge from a loving attitude for the benefit of others.
“Third, through perfect seeing, all discrimination is dissolved into a non-conceptual state.
“Finally, with an awareness of the void, one sincerely dedicates the results for the benefit of others. I have understood this to be the best of all ways.
“Just as a starving man cannot be fed by the knowledge of food but needs to eat, so too one needs to experience in meditation the meaning of emptiness. I understand more particularly that in order to arrive at perfect insight it is necessary to practice meritorious deeds and self-purification, without respite, in the intervals between meditations.
“In short, I saw that this meditator’s understanding of the emptiness of things, of their unity, of their indefinability, and of their non-differentiation corresponds to the four aspects of initiation according to the Vajrayana.
“In order to make this knowledge manifest in myself, I subdued my body, deprived it of food, harnessed my mind, and achieved equanimity in the face of all circumstances including the danger of death.”
(Milarepa speaking about his meditative insights to Marpa and Dakmema, The Life of Milarepa, p 78 – 79)