SB 11.15.29
agny-adibhir na hanyeta
muner yoga-mayam vapuh
mad-yoga-santa-cittasya
yadasam udakam yatha
Translation:
Just as the bodies of aquatics cannot be injured by water, similarly, the body of a yogi whose consciousness is pacified by devotion to Me and who is fully developed in yoga science cannot be injured by fire, sun, water, poison, and so forth.
Purport:
The creatures dwelling in the ocean are never injured by water; rather, they enjoy life within the watery medium. Similarly, for one skilled in the techniques of yoga, fending off attacks by weapons, fire, poison, and so on, is a recreational activity. Prahlada Maharaja was attacked by his father in all these ways, but because of his perfect Krsna consciousness he was not injured. The pure devotees of the Lord depend fully on the mercy of Lord Krsna, who possesses mystic opulences to an infinite degree and is therefore known as Yogesvara, the master of all mystic power. Because devotees are always connected to Lord Krsna, they do not feel any need to separately develop powers already possessed unlimitedly by their Lord, master and protector.
If a human being falls into the middle of the ocean he quickly drowns, whereas the fish enjoy happiness sporting in the same waves. Similarly, the conditioned souls have fallen into the ocean of material existence and are drowning in the reactions to their sinful activities, whereas the devotees recognize this world to be the potency of the Lord and enjoy pleasurable pastimes within it by fully engaging in the loving service of Lord Krsna.