Verse
स्पर्शान्कृत्वा बहिर्बाह्यां श्चक्षुश्चैवान्तरे भ्रुवोः ।प्राणापानौ समौ कृत्वा नासाभ्यन्तरचारिणौ ॥
Having put outside of himself all outward touches and concentrated the vision between the eyebrows and made equal the prāṇa and the apānau moving within the nostrils, having controlled the senses, the mind and the understanding, the sage devoted to liberation, from whom desire and wrath and fear have passed away, is ever free.
Gītā 5·27