I believe that the best way to be a better teacher is to be open to the idea that there is more to learn. (Rita Platt, teacher)
What is the goal of teaching? A good purpose might be stated this way: “The teacher’s goal is that the student learns and changes.” Wouldn’t any good teacher rejoice when one of his students exceeds the instructor’s best teaching effort and becomes more effective than his tutor? Such a teacher can take pride not just in his own work but that his students are continuing to learn.
If your gift is serving others, serve them well. If you are a teacher, teach well (Romans 12:7).