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.
Srimad Bhagavata Purana
श्रीमद्भागवतमहापुराणम्
मूल श्लोकः
तत्र तप्त्वा तपस्तीक्ष्णमात्मदर्शनमात्मवान् । सहैवाग्निभिरात्मानं युयोज परमात्मनि
tatra taptvā tapastīkṣṇamātmadarśanamātmavān | sahaivāgnibhirātmānaṃ yuyoja paramātmani
SB 9.6.54