"How can you be a Master of others (a Sifu), if you can't even master yourself." GrandMaster Henry Sue, Circular Tong Long Kung Fu
I love this quote. It makes it very clear to me the responsibility required of the Sifu to make sure he practices what he preaches. AND the same goes for the instructor too. How can you expect your students to be respectful and have humility if you do not? How can you expect them to be disciplined with their health and their training if you are not? How can you ask them to do things that you are not willing to do? Don't expect them to committed and enthusiastic if can't be either.
So a good instructor, or Sifu, follows the codes of martial morality, practices and hones his skills regularly, ponders the philosophies and theories of his martial arts, takes care of his mind and body, and keeps the best interests of his students and the community at heart. Leading by example will intstil the same habits in the next generation of martial artists under his tutelage.