Here is the Sanskrit anuvad, Hindi anuvad, and English translation of Shraddhatraya-Vibhaga Yoga Chapter 17, Verse 17.19.
Sanskrit
मूढग्राहेणात्मनो यत्पीडया क्रियते तपः । परस्योत्सादनार्थं वा तत्तामसमुदाहृतम् ॥ १७.१९ ॥
Hindi
जो तप मूढ़ता पूर्वक हठ से, मन, वाणी और शरीर की पीड़ा के सहित अथवा दूसरे के अनिष्ट करने के लिये किया जाता है —- वह तप तामस कहा गया है |
English
When self-control is incorrectly performed by a dull person and results simply in self-torture for the person who is trying to restrain himself, or when it is performed for the sake of causing injury to another person, then this self-control leads to nowhere but into sheer darkness and further along the path of the Tamas Guna.