Ramana Maharshi

…one should engage in the Quest of the Real Self, in order to win Liberation through quiescence of the mind.
All human thoughts are strung upon the thread of the thought "I am (this) body"; all thoughts (therefore) will cease if one dives into the Heart, seeking (the practical answer to the question) "Who am I?" or "From whence is this I?"

If all the thought-waves of the mind become stilled in this way, then the Truth of oneself (the Real Self) shines forth of itself as "I-I," the ego dies and happiness is patent (or obvious).

Verse 158. The Resolve to see the Real Self in the Heart, by mind concentrated on the question, "Who am I?", is the Quest, but not an intellectual conviction (about the Self) reached by reasoning.

Verse 159. This State (of Self-Realization) cannot be attained by any method, aside from the Quest in the Heart -- neither by lots of action, nor breath-regulation, nor any other device (e.g., mantra).
The State of being the Real Self, which is won by the Quest "Who is the doer?" or "Who is the separated one?" or "Who is the fallen one?" or "Who is the ignorant one?" is itself all the (four) paths.

Understand that the conviction that the universe has its being in the infinite sky of consciousness, namely the Self, is the firm seat for practicing mental peace.

So long as the ego is alive, the complexes of threes (e.g., seer, seeing, seen, etc.,) also appear; one should persevere in the practice (of the Quest) so long as (all) these complexes appear.

By fixing of the mind on the Real Self, you should conquer both the pleasure and the pain arising from the good and evil deeds (of your past) in the course of life in the world.

True subjugation of the mind is being the pure Consciousness (which one really is), by the dissolution of the delusion "I am the mind," (which comes) when the mind's activities are stilled (or extinguished). (20)

(20) Mind-Control, as commonly attempted, consists in mere inhibition (or suppression) of customary mental moods; this is unnatural, as pointed out in the line of the Gita, "all beings follow their ingrained natures; repression can do nothing." This repression on the mental plane is exactly on a par with the modern unscientific methods of preventing acute disease, like smallpox, by vaccination and similar methods that consist in sowing the seeds of disease. The natural method of subjugating the mind is given above.

Real breath-regulation is the being of the Enlightened One in his own real Nature, by rejecting the mind's habit of seeing the real as the world and persisting in the Quest of the Self.

Those that have devoted themselves to the Quest of the Self never stray aside from the path through error; the path of the Quest leads them on to the supreme State by its own light, like the Sun.

Since Non-remembrance (of the Real Self) is itself death, the only observance binding on the seeker (of the Self) is taking care not to forget, and no other.

Since observances do help, the seeker should honor them; but if and when they become hindrances to the practice of the Quest, he should then omit them.

Since the doing of one's own (routine) duties conduce to the forgetting of the Self, is it necessary to warn him that he should not engage in actions concerning others?

The mightiest tapas (mental discipline; spiritual practice and its effect) is to remain at peace, giving up egoism and the notion of doership (in ones actions), by the understanding that God does everything. (21)

Peace of mind, not inaction, is here recommended; God is the prompter from within Antaryami (Inner Guide); and when the mind is cool, free from passion, the urge to act is directly from Him and (then) may be obeyed.