It is a common saying that example is better than precepts. The example of the leading men in the right direction will very soon be followed by the common men.
Mahatma Gandhi set the example at his fag-end of life and his daily prayer meetings in the midst of gravest political occupation must be taken note of. So also in the Bhagavad-gita. The Arjuna in the gravest moment of warfare learnt the teachings of Bhagavad-gita & he changed his personal opinion in the manner of the fighting.