Verse
अनुबन्धं क्षयं हिंसाम् अनपेक्ष्य च पौरुषम् ।मोहादारभ्यते कर्म यत्तत्तामसमुच्यते ॥
The action undertaken from delusion (in mechanical obedience to the instincts, impulsions and unseeing ideas), without regarding the strength or capacity, without regarding the consequences, the waste of effort or injury to others, that is declared to be tamasic.
Gītā 18·25