Bhagavad Gita 17.5

शास्त्रविहितं घोरं तप्यन्ते ये तपो जना: |
दंभहङकारसंयुक्ता: कामराग्बलान्विता:

Translation

Some people perform stern austerities that are not enjoined by the scriptures, but rather motivated by hypocrisy and egotism. Impelled by desire and attachment,