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YOGA AND ITS PRACTICE
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tion than when one is sitting with a bent back. But, for the yogi, the erect posture is absolutely necessary. When the mind i becomes deeply absorbed, a spiritual current is felt to rise through the spine; and the passage for this current must be kept straight and open. More will be said about this subject in commenting on aphorisms 49 and 50 of this chapter.
प्रयत्नशैथिल्यानन्तसमापत्तिभ्याम् ॥४७॥ 47. Posture becomes firm and relaxed through control of
the natural tendencies of the body, and through medi
tation on the infinite. A good natural posture is very rare. Most people hold themselves badly and are subject to all sorts of physical.tensions. Asana must therefore be perfected by careful training. The aim is to achieve an effortless alertness, in which the body is perfectly steady and yet perfectly relaxed. Since a maladjusted body only expresses a tense and restless state of mind, we are told to calm our minds by meditating on what is infinite. Our minds are incapable of imagining the infinite Brahman; but instead, we can think of the limitless expanse of the sky.
ततो द्वन्द्वानभिघातः ॥४८॥ 48. Thereafter, one is no longer troubled by the dualities of
sense-experience. That is to say, by what the Gita calls“ the pairs of opposites," the apparent dualities of the phenomenal world—such as heat and cold, pleasure and pain, good and evil, etc.
Such complete mastery of the body does not, of course, come through posture alone. It arises from a state of absorption in the consciousness of God. Patanjali goes on to describe the further practices which are necessary in order to reach this state.