Śatapatha Brāhmaṇa ("of a hundred paths") 3.4.3.8

3.4.3.8

te 'viduḥ | ayaṃ vai no virakṣastamo 'syaiva rūpamasāma tena rakṣāṃsyatimokṣyāmahe tena svargaṃ lokaṃ samaśnuviṣyāmaha iti te 'gnireva rūpamabhavaṃstena rakṣāṃsyatyamucyanta tena svargaṃ lokaṃ samāśnuvata tatho evaiṣa etadagnereva rūpam bhavati tena rakṣāṃsyatimucyate tena svargaṃ lokaṃ samaśnute sa vai samidhamevābhyādadhadavāntaradīkṣāmupaiti

They became aware,--'He verily is the greatest repeller of the Rakshas among us; let us be like him: thereby we shall escape from the Rakshas, thereby we shall attain to the heavenly world.' They accordingly became like Agni, and thereby escaped from the Rakshas and attained to the heavenly world. And in like manner does this one now become like Agni, and thereby escape from the Rakshas and attain to the heavenly world. It is in putting a kindling-stick on (the Âhavanîya fire) that he enters upon the Avântaradîkshâ.