योऽग्नौ तिष्ठन्नग्नेरन्तरो यमग्निर्न वेद यस्याग्निः शरीरं योऽग्निमन्तरो यमयत्येष त आत्मान्तर्याम्यमृतः ॥बृह. ३,७.५ ॥
In plain words
He who dwells in fire, yet is within fire, whom fire does not know, whose body fire is, who from within controls fire — he is thy Self, the inner controller, the immortal.