Verse
समं कायशिरोग्रीवं धारयन्नचलं स्थिरः ।संप्रेक्ष्य नासिकाग्रं स्वं दिशश्चानवलोकयन् ॥
samaṃ kāyaśirogrīvaṃ dhārayannacalaṃ sthiraḥsaṃprekṣya nāsikāgraṃ svaṃ diśaścānavalokayan
Holding the body, head and neck erect, motionless (the posture proper to the practice of Rajayoga), the vision drawn in and fixed between eyebrows, not regarding the regions, the mind kept calm and free from fear and the vow of Brahmacharya observed, the whole controlled mentality turned to Me (the Divine), he must sit firm in Yoga, wholly given up to Me (so that the lower action of the consciousness shall be merged in the higher peace).
Gītā 6·13