Paramatma (SB cantos 7 - 12)
Srimad-Bhagavatam
SB Canto 7
SB 7.1.9, Purport:
The word ātmānam in this verse means paramātmānam. The Paramātmā, or Supersoul, is situated in the core of everyone's heart (antataḥ). This is confirmed in Bhagavad-gītā (18.61). Īśvaraḥ sarva-bhūtānāṁ hṛd-deśe 'rjuna tiṣṭhati. The īśvara, the Supreme Personality of Godhead, being situated in everyone's heart, gives directions to everyone in terms of one's capabilities in taking the instructions. The instructions of Bhagavad-gītā are open to everyone, but some people understand them properly, whereas others understand them so improperly that they cannot even believe in the existence of Kṛṣṇa, although reading Kṛṣṇa's book. Although the Gītā says śrī-bhagavān uvāca, indicating that Kṛṣṇa spoke, they cannot understand Kṛṣṇa.