Bhagwad Gita
Chapter 17, Verse 19
मूढग्राहेणात्मनो यत्पीडया क्रियते तपः।परस्योत्सादनार्थं वा तत्तामसमुदाहृतम्।।17.19।।
And those penances and austerities which are performed foolishly by means of obstinate self-torture, or to destroy or injure others, are said to be in the mode of ignorance.