Srimad Bhagavatam Canto 08, Chapter 03, Text 27

SB 8.3.27

 hrdi yoga-vibhavite
yogino yam prapasyanti
 yogesam tam nato ’smy aham
Translation by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada: 
I offer my respectful obeisances unto the Supreme, the Supersoul, the master of all mystic yoga, who is seen in the core of the heart by perfect mystics when they are completely purified and freed from the reactions of fruitive activity by practicing bhakti-yoga.
Purport by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada: 
The King of the elephants, Gajendra, simply accepted that there must be someone who has created this cosmic manifestation and has supplied its ingredients. This should be admitted by everyone, even the most determined atheists. Why, then, do the nondevotees and atheists not admit this? The reason is that they are polluted by the reactions of their fruitive activities. One must be freed from all the dirt accumulated within the heart due to fruitive activities performed one after another. One must wash off this dirt by practicing bhakti-yoga. Yoga-randhita-karmanah. As long as one is covered by material nature’s modes of ignorance and passion, there is no possibility of understanding the Supreme Lord. Tada rajas-tamo-bhavah kama-lobhadayas ca ye. When one is freed from the modes of ignorance and passion, one becomes free from the lowest qualities — kama and lobha, lust and greed.
Nowadays there are so many yoga schools to encourage people in developing their lusty desires and greed through the practice of yoga. People are therefore very much fond of so-called yoga practice. The actual practice of yoga, however, is described here. As authoritatively stated in the Srimad-Bhagavatam (12.13.1), dhyanavasthita-tad-gatena manasa pasyanti yam yoginah: a yogi is one who always meditates on the lotus feet of the Supreme Personality of Godhead. This is also confirmed in the Brahma-samhita (5.38):
 santah sadaiva hrdayesu vilokayanti
yam syamasundaram acintya-guna-svarupam
 govindam adi-purusam tam aham bhajami
“I worship Govinda, the primeval Lord, who is Syamasundara, Krsna Himself, with inconceivable innumerable attributes, whom the pure devotees see in their heart of hearts with the eye of devotion tinged with the salve of love.” The bhakti-yogi constantly sees Syamasundara — beautiful Lord Krsna with His blackish bodily hue. Because the King of the elephants, Gajendra, thought himself an ordinary animal, he thought himself unfit to see the Lord. In his humility, he thought that he could not practice yoga. In other words, how can those who are like animals in the bodily concept of life, and who have no purity of consciousness, practice yoga? In the present day, people who have no control over their senses, who have no understanding of philosophy and who do not follow religious principles or rules and regulations are nonetheless pretending to be yogis. This is the greatest anomaly in the practice of mystic yoga.
Srimad Bhagavatam Canto 08, Chapter 03, Text 26
Srimad Bhagavatam Canto 08, Chapter 03, Text 28