Shiva Purana

siva.sh/siva-purana/saturda-samhita/15/64

अग्निरेको द्विजातीनां निश्श्रेयसकरः परः ।। गुरुर्देवो व्रतं तीर्थं सर्वमग्निर्विनिश्चितम् ।। ६४ ।।

sanskrit

Fire alone is the greatest means of salvation for the brahmins. He is the preceptor, the lord, the sacred rite, the holy centre. Certainly everything is fire.

english translation

agnireko dvijAtInAM nizzreyasakaraH paraH || gururdevo vrataM tIrthaM sarvamagnirvinizcitam || 64 ||

hk transliteration by Sanscript