Chapter 17 · verse 19 · gita.yoga.org

Bhagavad Gita 17.19

मूढग्राहेणात्मनो यत्पीडया क्रियते तपः।परस्योत्सादनार्थं वा तत्तामसमुदाहृतम्

That austerity which is practised out of a foolish notion, with self-torture, or for the purpose of destroying another, is declared to be of the Tamasic nature.