It's something that we have to be wary of both in our vocation and in life generally. The church example that I'll give is a pastor giving a passionate sermon about the importance of attending worship services regularly with the choir sitting behind her. Of course, most of the people listening are people who already attend worship services regularly. The people who need to hear the message are the ones that are not there.
And, that's kind of what it means in everyday life too. It means that we are talking about a problem with people who already agree with us or are already doing what we want. In effect, we are wasting our time and energy because we are not talking with the right people. The choice is to find the right people, or change the message to one that is more helpful for our audience.
Come back tomorrow, when I'll talking about being Up a Creek without a Paddle.