BṚHADĀRAṆYAKA UPANISHAD · 6.4.2

स ह प्रजापतिर् ईक्षां चक्रे -- हन्तास्मै प्रतिष्ठां कल्पयानीति स स्त्रियं ससृजे ।
तां सृष्ट्वाध उपास्त ।
तस्मात् स्त्रियम् अध उपासीत ।
स एतं प्राञ्चं ग्रावाणम् आत्मन एव समुदपारयत् ।
तेनैनाम् अभ्यसृजत ॥

sa ha prajāpatir īkṣāṃ cakre -- hantāsmai pratiṣṭhāṃ kalpayānīti sa striyaṃ sasṛje ।
tāṃ sṛṣṭvādha upāsta ।
tasmāt striyam adha upāsīta ।
sa etaṃ prāñcaṃ grāvāṇam ātmana eva samudapārayat ।
tenainām abhyasṛjata ॥

Prajâpati ('Lord of creatures') bethought himself: 'Come, let me provide him a firm basis!' So he created woman. When he had created her, he revered her below.--Therefore one should revere woman below.--He stretched out for himself that stone which projects. With that he impregnated her.

Robert Ernest Hume · The Thirteen Principal Upanishads (1921), Bṛhadāraṇyaka VI.4