अथान्यत्राप्युक्तम् यदा वै बहिर्विद्वान्मनो नियम्येन्द्रियार्थान् च प्राणो निवेशयित्वा निःसङ्कल्पस्ततस्तिष्ठेत् अप्राणादिह यस्मात्सम्भूतः प्राणसंज्ञको जीवस्तस्मात्प्राणो वै तुर्याख्ये धारयेत्प्राणम् इत्येवं ह्याह अचित्तं चित्तमध्यस्तमचिन्त्यं गुह्यमुत्तमम् ।तत्र चित्तं निधायेत तच्च लिङ्गं निराश्रयम् ॥ ॥६.१९ ॥
In plain words
And it is said elsewhere too: When a knower has held his mind back from what is outside, and has settled the breath and the objects of the senses, then let him stand free of all willing. And since the living being here, which is called breath, has come to be from what is not breath, let him therefore hold the breath in what is called the fourth. So it is said: "The thoughtless, set in the midst of thought, unthinkable, hidden, highest — there let a man set his thought, and that mark which has no support."