KAṬHA UPANISHAD · 2.1.1

पराञ्चि खानि व्यतृणत् स्वयम्भूस्तस्मात्पराङ्पश्यति नान्तरात्मन् ।
कश्चिद्धीरः प्रत्यगात्मानमैक्षदावृत्तचक्षुरमृतत्वमिच्छन् ॥ १॥

parāñci khāni vyatṛṇat svayambhūstasmātparāṅpaśyati nāntarātman ।
kaściddhīraḥ pratyagātmānamaikṣadāvṛttacakṣuramṛtatvamicchan ॥ 1॥

The Self-born hath set the doors of the body to face outward, therefore the soul of a man gazeth outward and not at the Self within; hardly a wise man here and there desiring immortality turneth his eyes inward and seeth the Self within him.

Sri Aurobindo · CWSA 18, p. 117