SB 9.4.70
tapo vidya ca vipranam
nihsreyasa-kare ubhe
te eva durvinitasya
kalpete kartur anyatha
Translation by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada:
For a brahmana, austerity and learning are certainly auspicious, but when acquired by a person who is not gentle, such austerity and learning are most dangerous.
Purport by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada:
It is said that a jewel is very valuable, but when it is on the hood of a serpent, it is dangerous despite its value. Similarly, when a materialistic nondevotee achieves great success in learning and austerity, that success is dangerous for all of society. So-called learned scientists, for example, invented atomic weapons that are dangerous for all humanity. It is therefore said, manina bhusitah sarpah kim asau na bhayankarah. A serpent with a jewel on its hood is as dangerous as a serpent without such a jewel. Durvasa Muni was a very learned brahmana equipped with mystic power, but because he was not a gentleman, he did not know how to use his power. He was therefore extremely dangerous. The Supreme Personality of Godhead is never inclined toward a dangerous person who uses his mystic power for some personal design. By the laws of nature, therefore, such misuse of power is ultimately dangerous not for society but for the person who misuses it.