This is remarkably practical advice. A wise person should not walk into a room of hardworking, sincere people and announce, 'All action is ultimately meaningless.' That may be philosophically defensible, but it would shatter the faith of those who are not ready to hear it.
Instead, the wise person leads by example. They perform their own duties with grace and skill, rooted in yoga, and in doing so they naturally inspire others to do the same. Teaching here happens through conduct, not through lectures.