The Kagyu lineage of Buddhist Practice- The course of Practice: Quiescene and Insight-Milarepa

After initial refuge [taking disciples who are vessels (of Dharma) under the guidance of a qualified lama should generate the mind aimed at enlightenment, compile the stores (of merit and gnosis) by performing the seven acts of worship, of guru yoga, mandala offerings, prayer, and so on, and clear away the blockage (of previous bad action) by meditation and repetition of the hundred-syllable Vajrasattva mantra. 

It is of utmost importance to persevere in all this for months and even years until the signs of development occur. Even after such signs and indications have occurred, you must still achieve spontaneous concentration by the gradual process of actual realization states based on the store of previously compiled merit.

The achievement of "spontaneous" or "effortless" concentration is not a spontaneous or effortless matter. The process of Quiescene through one-pointed concentration, the prerequisite for the analytic practice aimed at transcendent insight, is a major consuming task.

Mila explains it as follows:(In the practice of quiescence) beginners achieve mental stability by degrees, their stream of thought (at first) breaking through like a mountain cascade, until eventually the mind remains naturally focused wherever it is placed. This is termed "mental stability", and since it is the foundation of the absorption levels (dhyana), there is no advancement without it.

The process advances through seven phases before reaching the level of spontaneous concentration. Advancement involves learning to correct various degrees of antithetical mental functions - particularly "mental sinking" or sluggishness through the mind's tendency to be overtly absorbed in its object, and "excitation" through an over-reactivity or scattering of the attention from the object to other things.

It also involves the suppression of mental discursiveness or thought-flow instigated by the habitual, compulsive tendency to identify and name the objects of experience. To achieve correct concentration, the yogi must develop the antidotes: recollective awareness, which serves to hold attention to the object by "remembering" the situation and instructions for concentration, and critical awareness, which assesses the mental situation at any moment and determines how it might be going astray.

Quiescene involves suppression of thought-flow by concentration, while the complementary process, analytic insight, involves penetration of the though process through the exercise of intellect while in a state of concentrative Quiescene. The practice of insight is aimed at the experience of transcendent wisdom through investigation of the true condition of persons and things-their egolessness or voidness. 

It begins with learning the facts and teachings and then reflecting on their import in detail and depth. Study was not rejected by Milarepa, only over-interest in books. Real training of the intellect is essential to the process of analytic insight. Mila explains this as follows.

Analytic meditation that subjects to repeated examination the mistaken assumptions involved in learning and reflecting (on the teachings of) an experienced, skillfull lama concerning the explicit import of the (scriptures), when firmly combined with previously developed Quiescene concentration, is termed focusing meditation. During such an experience the understanding of the actual condition (of things, i.e., their voidness of identity), the explicit goal of such analysis, is termed understanding.

The various mental events and apparitional experiences occurring in the mind equipoised in such correct understanding and firmly based on Quiescene are termed (developmental) experiences. The direct confrontation of the goal, the natural state, supported by these experiences in realization.

Reference: Drinking the Mountain Stream: Songs of Tibet's Beloved Saint: Milarepa: Translated By Lama Kunga Rinpoche & Brian Cutillo