उत्सीदेयुरिमे लोका न कुर्यां कर्म चेदहम् ।सङ्करस्य च कर्ता स्यामुपहन्यामिमाः प्रजाः ॥
utsīdeyurime lokā na kuryāṃ karma cedaham |saṅkarasya ca kartā syāmupahanyāmimāḥ prajāḥ ||
If I did not perform action, these worlds would collapse; I would become the author of confusion, and I would destroy these beings.
Explanation
Krishna is telling Arjuna why he himself keeps acting, though he has nothing left to gain. If he stopped, people would follow his example, social and moral order would break down (the word saṅkara means mixing or confusion, often read as disorder of social duties), and the world would suffer. The point is that those who are looked up to carry a responsibility to act well.