Bhagavad Gita Chapter 3 Verse 21 भगवद् गीता अध्याय 3 श्लोक 21 यद्यदाचरति श्रेष्ठस्तत्तदेवेतरो जनः। स यत्प्रमाणं कुरुते लोकस्तदनुवर्तते।।3.21।। हिंदी अनुवाद - स्वामी रामसुख दास जी ( भगवद् गीता 3.21) ।।3.21।।श्रेष्ठ मनुष्य जोजो आचरण करता है दूसरे मनुष्य वैसावैसा ही आचरण करते हैं। वह जो कुछ प्रमाण देता है दूसरे मनुष्य उसीके अनुसार आचरण करते हैं। Rudra Vaishnava Sampradaya - Commentary How the performance of prescribed Vedic actions acts as an incentive to the masses is what Lord Krishna is emphasising here. That line of reasoning that great personalities accept as authoritative people will also follow. Brahma Vaishnava Sampradaya - Commentary The great personalities naturally set the example for the common man to follow in the manner in which they speak and in the way in which they act. This is Lord Krishnas meaning. Shri Vaishnava Sampradaya - Commentary So understanding that the whole Earth benefits from the performance of prescribed Vedic activities, one should act altruistically not for themselves but for the welfare of the world. This is the meaning Lord Krishna is conveying. The word sresthah means great personality expert in the conclusions of the Vedas. Whatever actions such a great person performs others will try to follow. It may be that a certain activity should be performed on a special day. The common people will wait to see how a great person takes the initiative on such an action and then they will follow suit. Hence the great personalities should always act in an exemplary manner to set the standard for the world. In this way they inspire everyone to perform prescribed Vedic actions according to the qualification of ones varna or caste in life and ones asrama or stage in life. If one fails to do this by neglect or omission one commits sin by omitting to help benefit the welfare of the world by their example and the consequence will be one will fall down from the path they achieved after many lifetimes. Kumara Vaishnava Sampradaya - Commentary So understanding that the whole Earth benefits from the performance of prescribed Vedic activities, one should act altruistically not for themselves but for the welfare of the world. This is the meaning Lord Krishna is conveying. The word sresthah means great personality expert in the conclusions of the Vedas. Whatever actions such a great person performs others will try to follow. It may be that a certain activity should be performed on a special day. The common people will wait to see how a great person takes the initiative on such an action and then they will follow suit. Hence the great personalities should always act in an exemplary manner to set the standard for the world. In this way they inspire everyone to perform prescribed Vedic actions according to the qualification of ones varna or caste in life and ones asrama or stage in life. If one fails to do this by neglect or omission one commits sin by omitting to help benefit the welfare of the world by their example and the consequence will be one will fall down from the path they achieved after many lifetimes.