सहैवाग्निभिरात्मानं युयोज परमात्मनि ॥ ५४ ॥
tatra — in the forest; taptvā — executing austerity; tapaḥ — the regulative principles of austerity; tīkṣṇam — very severely; ātma-darśanam — which helps self-realization; ātmavān — conversant with the self; saha — with; eva — certainly; agnibhiḥ — fires; ātmānam — the personal self; yuyoja — he engaged; parama-ātmani — dealing with the Supreme Soul.
When Saubhari Muni, who was quite conversant with the self, went to the forest, he performed severe penances. In this way, in the fire at the time of death, he ultimately engaged himself in the service of the Supreme Personality of Godhead.
At the time of death, fire burns the gross body, and if there is no more desire for material enjoyment the subtle body is also ended, and in this way a pure soul remains. This is confirmed in Bhagavad-gītā (tyaktvā dehaṁ punar janma naiti). If one is free from the bondage of both the gross and subtle material bodies and remains a pure soul, he returns home, back to Godhead, to be engaged in the service of the Lord. Tyaktvā dehaṁ punar janma naiti mām eti: he goes back home, back to Godhead. Thus it appears that Saubhari Muni attained that perfect stage.