This is a wonderful teaching given by Geshe
Rabten.
Concentration is important in both Dharma practice and ordinary
life. The Tibetan word for the practice of concentration is zhi-nay
(zhi-gNas). Zhi means peace and nay means to dwell; zhi-nay, then,
is dwelling in peace or being without busyness.
If we do not carefully watch the mind it may seem that it is
peaceful. However, when we really look inside we see that this is
not so. Mind does not rest on the same object for even a single
second. It flutters around like a banner flapping in the wind. No
sooner does mind settle on one object than it is carried away by
another. Even if we live in a cave on a high mountain the mind
moves incessantly. When we are on the top of a tall city building
we can look down and see how busy the city is, but when we are
walking on the streets we are aware of only a fraction of the
busyness. Similarly, if we do not investigate correctly we will
never be aware of how busy the mind really is.
Primary consciousness itself is pure and stainless, but gathered
around it are fifty-one secondary mental elements, some of which
are positive, some negative and some neutral. Of these secondary
elements, in ordinary beings, the negative ones are stronger than
the positive. Most people never attempt to gain control of these
secondary mental elements; if they did they would be amazed at how
difficult such a task is. Because the negative elements have
dominated the mind for countless lifetimes, overcoming them will
require tremendous effort. Yet zhi-nay cannot be experienced until
they have been totally subdued.
Thus the busyness of the mind is mind-produced. This means that
a mental rather than a physical effort is required to eliminate it.
Nonetheless, when engaging in an intensive effort to develop
zhi-nay it is important to make use of certain secondary factors of
a physical nature. For example, the place where one practises
should be clean, quiet, close to nature and pleasing to the mind.
And friends that visit should be peaceful and virtuous. One’s body
should be strong and free from disease.
(To read further, check out http://blog.tsemtulku.com/tsem-tulku-rinpoche/great-lamas-masters/the-perfection-of-concentration-by-geshe-rabten-rinpoche.html )