Bhagavatapurana 1.6.16

1.6.16

tasmin nirmanuje 'raṇye pippalopastha āśritaḥ /
ātmanātmānam ātmasthaṃ yathāśrutam acintayam //

16. In that forest unknown to man, I sat down under a Pippala tree, and in the manner I had learnt from the sages, I meditated on the Paramatman present in my heart, with all the power of my understanding.