Text 19

मूढग्राहेणात्मनो यत्पीडया क्रियते तपः ।
परस्योत्सादनार्थं वा तत्तामसमुदाहृतम् ॥१९॥

mūḍha-grāheṇātmano yat
pīḍayā kriyate tapaḥ
parasyotsādanārthaḿ vā
tat tāmasam udāhṛtam

Translation:

Penance performed out of foolishness, with self-torture or to destroy or injure others, is said to be in the mode of ignorance.

Purport:

There are instances of foolish penance undertaken by demons like Hiranyakasipu, who performed austere penances to become immortal and kill the demigods. He prayed to Brahma for such things, but ultimately he was killed by the Supreme Personality of Godhead. To undergo penances for something which is impossible is certainly in the mode of ignorance.