Bṛhadāraṇyaka Upaniṣad ("Great Forest Teaching") 2.2.1

2.2.1

yo ha vai śiśum̐ sādhānam̐ sapratyādhānam̐ sasthūṇam̐ sadāmaṃ veda sapta hadviṣato bhrātṛvyānavaruṇaddhi | ayaṃ vāva śiśuryo'yaṃ madhyamaḥ prāṇastasyedamevādhānamidaṃ pratyādhānaṃ prāṇaḥ sthūṇānnaṃ dāma

Verily he who knows the babe with his place, his chamber, his post, and his rope, he keeps off the seven relatives who hate him. Verily by the young is meant the inner life, by his place this (body), by his chamber this (head), by his post the vital breath, by his rope the food.