The Bhagavad Gita · Chapter 3 · verse 3.21
Whatever a great person does, others follow. Whatever standard they set, the world pursues.
Sanskrit (Devanagari)
यद्यदाचरति श्रेष्ठस्तत्तदेवेतरो जनः। स यत्प्रमाणं कुरुते लोकस्तदनुवर्तते॥
Transliteration
yad yad ācarati śreṣṭhas tat tad evetaro janaḥ; sa yat pramāṇaṁ kurute lokas tad anuvartate
English translation
Whatever a great person does, others follow. Whatever standard they set, the world pursues.
Meaning — what the verse is actually saying
Leadership is by demonstration, not declaration. People absorb behaviour they observe more reliably than instruction they receive. If you have any role of influence — parent, teacher, manager, founder — what you do quietly is your real curriculum.
Modern practice — what to do today because of this
Before correcting someone you have influence over, ask: am I demonstrating, in my own behaviour, what I am asking them to do? If no, fix that first. The correction without the demonstration teaches the opposite of what it intends.