SB 8.16.20

upatiṣṭhasva puruṣaṁ
 bhagavantaṁ janārdanam
sarva-bhūta-guhā-vāsaṁ
 vāsudevaṁ jagad-gurum
Word for word: 
upatiṣṭhasva — just try to worship; puruṣam — the Supreme Person; bhagavantam — the Personality of Godhead; janārdanam — who can kill all the enemies; sarva-bhūta-guhā-vāsam — living within the core of the heart of everyone; vāsudevam — Vāsudeva, Kṛṣṇa, who is all-pervading and is the son of Vasudeva; jagat-gurum — the spiritual master and teacher of the whole world.
Translation: 
My dear Aditi, engage in devotional service to the Supreme Personality of Godhead, who is the master of everything, who can subdue everyone’s enemies, and who sits within everyone’s heart. Only that Supreme Person — Kṛṣṇa, or Vāsudeva — can bestow all auspicious benedictions upon everyone, for He is the spiritual master of the universe.
Purport: 

With these words, Kaśyapa Muni tried to pacify his wife. Aditi made her appeal to her material husband. Of course, that is nice, but actually a material relative cannot do anything good for anyone. If anything good can be done, it is done by the Supreme Personality of Godhead, Vāsudeva. Therefore, Kaśyapa Muni advised his wife, Aditi, to begin worshiping Lord Vāsudeva, who is situated in everyone’s heart. He is the friend of everyone and is known as Janārdana because He can kill all enemies. There are three modes of material nature — goodness, passion and ignorance — and above material nature, transcendental to material nature, is another existence, which is called śuddha-sattva. In the material world, the mode of goodness is considered the best, but because of material contamination, even the mode of goodness is sometimes overpowered by the modes of passion and ignorance. But when one transcends the competition between these modes and engages himself in devotional service, he rises above the three modes of material nature. In that transcendental position, one is situated in pure consciousness. Sattvaṁ viśuddhaṁ vasudeva-śabditam (Bhāg. 4.3.23). Above material nature is the position called vasudeva, or freedom from material contamination. Only in that position can one perceive the Supreme Personality of Godhead, Vāsudeva. Thus the vasudeva condition fulfills a spiritual necessity. Vāsudevaḥ sarvam iti sa mahātmā sudurlabhaḥ. When one realizes Vāsudeva, the Supreme Personality of Godhead, he becomes most exalted.

Paramātmā (Vāsudeva) is situated in everyone’s heart, as confirmed in Bhagavad-gītā. The Lord says:

teṣāṁ satata-yuktānāṁ
 bhajatāṁ prīti-pūrvakam
dadāmi buddhi-yogaṁ taṁ
 yena mām upayānti te

“To those who are constantly devoted and who worship Me with love, I give the understanding by which they can come to Me.” (Bg. 10.10)

īśvaraḥ sarva-bhūtānāṁ
 hṛd-deśe ’rjuna tiṣṭhati

“The Supreme Lord is situated in everyone’s heart, O Arjuna.” (Bg. 18.61)

bhoktāraṁ yajña-tapasāṁ
 sarva-loka-maheśvaram
suhṛdaṁ sarva-bhūtānāṁ
 jñātvā māṁ śāntim ṛcchati

“The sage who knows Me as the ultimate purpose of all sacrifices and austerities, the Supreme Lord of all planets and demigods and the benefactor and well-wisher of all living entities attains peace from the pangs of material miseries.” (Bg. 5.29)

Whenever one is perplexed, let him take shelter of the lotus feet of Vāsudeva, Kṛṣṇa, who will give the devotee intelligence to help him surpass all difficulties and return home, back to Godhead. Kaśyapa Muni advised his wife to seek shelter at the lotus feet of Vāsudeva, Kṛṣṇa, so that all her problems would be very easily solved. Thus Kaśyapa Muni was an ideal spiritual master. He was not so foolish that he would present himself as an exalted personality, as good as God. He was actually a bona fide guru because he advised his wife to seek shelter at the lotus feet of Vāsudeva. One who trains his subordinate or disciple to worship Vāsudeva is the truly bona fide spiritual master. The word jagad-gurum is very important in this regard. Kaśyapa Muni did not falsely declare himself to be jagad-guru, although he actually was jagad-guru because he advocated the cause of Vāsudeva. Actually, Vāsudeva is jagad-guru, as clearly stated here (vāsudevaṁ jagad-gurum). One who teaches the instructions of Vāsudeva, Bhagavad-gītā, is as good as vāsudevaṁ jagad-gurum. But when one who does not teach this instruction — as it is — declares himself jagad-guru, he simply cheats the public. Kṛṣṇa is jagad-guru, and one who teaches the instruction of Kṛṣṇa as it is, on behalf of Kṛṣṇa, may be accepted as jagad-guru. One who manufactures his own theories cannot be accepted; he becomes jagad-guru falsely.