Verse
अशास्त्रविहितं घोरं तप्यन्ते ये तपो जनाः ।दम्भाहंकारसंयुक्ताः कामरागबलान्विताः ॥
aśāstravihitaṃ ghoraṃ tapyante ye tapo janāḥdambhāhaṃkārasaṃyuktāḥ kāmarāgabalānvitāḥ
The men who perform violent austerities, contrary to the Shastra, with arrogance and egoism, impelled by the force of their desires and passions, men of unripe minds tormenting the aggregated elements forming the body and troubling Me also, seated in the body, know these to be Asuric in their resolves.
Gītā 17·5