Śatapatha Brāhmaṇa ("of a hundred paths") 3.1.3.4

3.1.3.4

ta u haita ūcuḥ | devā ādityā yadasmānanvajanimā tadamuyeva bhūddhantemaṃ vikaravāmeti taṃ vicakruryathāyam puruṣo vikṛtastasya yāni māṃsāni saṃkṛtya saṃnyāsustato hastī samabhavattasmādāhurna hastinam pratigṛhṇīyātpuruṣājāno hi hastīti yamu ha tadvicakruḥ sa vivasvānādityastasyemāḥ prajāḥ

The gods, sons of Aditi, then spake, 'That which was born after us must not be lost: come, let us fashion it.' They accordingly fashioned it as this man is fashioned. The flesh which was cut off him, and thrown down in a lump, became the elephant: hence they say that one must not accept an elephant (as a gift), since the elephant has sprung from man. Now he whom they thus fashioned was Vivasvat, the Âditya (or the sun); and of him (came) these creatures.