Śatapatha Brāhmaṇa ("of a hundred paths") 9.3.1.6

9.3.1.6

śira eva dyauḥ | nakṣatrāṇi keśāstadetadviśvaṃ cakṣurevādityaḥ sa narastadavastācorṣṇo bhavatyavastāddhi diva ādityastadasyaitaciro vaiśvānara ātmāyamagniścita ātmāyamagniścita ātmānamevāsyaitatsaṃskṛtya śiraḥ pratidadhāti

The sky is the (upper part of the) head, and the stars are the hair; it is the All, and Âditya (the sun) is the eye, he is the man: it is in the lower part of the (upper) head, for the sun is below the sky. Vaisvânara is the head thereof, and this built-up Agni (the altar) is the body: thus, having completed his body, he restores the head thereto.