aśhāstra-vihitaṁ ghoraṁ tapyante ye tapo janāḥ
dambhāhankāra-sanyuktāḥ kāma-rāga-balānvitāḥ||5||

Meaning : Lord Krishna said:
Those people who perform severe austerities (tapas) not approved by the scriptures, doing them with hypocrisy, ego, desire, and attachment — they are driven by pride and passion.