Shankaracharya's commentary, trans. Alladi Mahadeva Sastry (1897)
[1]The austerity which is practised out of a foolish notion, with self-torture, or for the purpose of ruining another, is declared to be Tamasic.
BG 17.19
मूढग्राहेणात्मनो यत् पीडया क्रियते तपः । परस्योत्सादनार्थं वा तत् तामसम् उदाहृतम् ॥
mūḍha-grāheṇātmano yat pīḍayā kriyate tapaḥ | parasyotsādanārthaṃ vā tat tāmasam udāhṛtam ||
"Tāmasic tapas: done with foolish delusion, self-torture, or to destroy another — declared tāmasic."
All public-domain translations
4 translations · all pre-1928 or released to public domain · sources
Swami Swarupananda, Srimad Bhagavad Gita (1909)
[4]That austerity which is practised out of a foolish notion, with self-torture or for the purpose of ruining another, is declared to be Tamasika.
K.T. Telang, Sacred Books of the East Vol. 8 (1882)
[9]Penance practised through foolishness, with self-torture, or for the purpose of destroying another, is called dark.
K.M. Ganguli, The Mahabharata, Bhishma Parva (1883–96)
[13]That penance which is practised through ignorance and foolishness, with self-torture, or for the purpose of destroying another, is said to be of the quality of darkness.