Bhagavad-gītā As It Is · Text 6.11
Yoga practice, posture and moderation
शुचौ देशे प्रतिष्ठाप्य स्थिरमासनमात्मन: ।
नात्युच्छ्रितं नातिनीचं चैलाजिनकुशोत्तरम् ॥ ११ ॥
तत्रैकाग्रं मन: कृत्वा यतचित्तेन्द्रियक्रिय ।
उपविश्यासने युञ्ज्याद्योगमात्मविशुद्धये ॥ १२ ॥
śucau deśe pratiṣṭhāpya
sthiram āsanam ātmanaḥ
nāty-ucchritaṁ nāti-nīcaṁ
cailājina-kuśottaram
tatraikāgraṁ manaḥ kṛtvā
yata-cittendriya-kriyaḥ
upaviśyāsane yuñjyād
yogam ātma-viśuddhaye
To practice yoga, one should go to a secluded place and should lay kuśa grass on the ground and then cover it with a deerskin and a soft cloth. The seat should be neither too high nor too low and should be situated in a sacred place. The yogī should then sit on it very firmly and practice yoga to purify the heart by controlling his mind, senses and activities and fixing the mind on one point.
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