Shatapatha Brahmana · Chapter 13.1.4

prajāpatiraśvamedhamasṛjata so'smātsṛṣṭaḥ parāṅaitsa diśo'nuprāviśattaṃ devāḥ praiṣamaicchaṃstamiṣṭibhiranuprāyuñjata tamiṣṭibhiranvaicchaṃstamiṣṭibhiranvavindan yadiṣṭibhiryajate'śvameva tanmedhyaṃ yajamāno'nvicchati -

sāvitryo bhavanti iyaṃ vai savitā yo vā asyāṃ nilayate yo'nyatraityasyāṃ vāva tamanuvindanti na vā imāṃ kaścana tiryaṅnordhvo'tyetumarhati yatsāvitryo bhavantyaśvasyaivānuvittyai -

tadāhuḥ pra vā etadaśvo mīyate yatparāṅeti na hyenaṃ pratyāvartayantīti yatsāyaṃ dhṛtīrjuhoti kṣemo vai dhṛtiḥ kṣemo rātriḥ kṣemeṇaivainaṃ dādhāra tasmātsāyammanuṣyāśca paśavaśca kṣemyā bhavantyatha yatprātariṣṭibhiryajata icchatyevainaṃ tattasmāddivā naṣṭaiṣa eti yadveva sāyaṃ dhṛtīrjuhoti prātariṣṭibhiryajate yogakṣemameva tadyajamānaḥ kalpayate tasmādyatraitena yajñena yajante kḷptaḥ prajānāṃ yogakṣemo bhavati -