In plain words
You must first practise and then teach it to the children. He alone who practises and then teaches is an ācārya. If a lecturer smokes a cigarette in college, the student too will do the same. If you ask, “Hey you, why are you smoking a cigarette?”: “Sir! You too are doing the same, aren't you!” he says. What answer can the lecturer give to that? No reply! So if the lecturer is to teach students good habits, he must first keep away from bad habits. He must do good himself and teach the children good. That is right teaching. Only then will the student's goodness come out. Repenting of the wrongs he has done: “Sir! I did many wrongs without knowing”, he admits, and from that day on he grows into a good boy.
I love children very much and give them what they need. But at times, if they do something wrong, I am very stern. Then the children themselves come: “Swami! What we did was wrong. Forgive us. From now on we will not do such a wrong”, they say. At those words Swami melts. “My dears! At least from now on, set your conduct right. Whatever I do is only for your good”, I tell them. Teachers too must teach children in this way.
Question: What is the chief quality a teacher should have?
A teacher must teach the children whatever seems good to him, and keep following it himself. He must give the children an ideal life. I shall tell you a small example of this. In the days when I was studying in the third and fourth classes, there was a teacher named Iyengar in our school. In those days children had great respect for the guru when they saw him, and fear too! If they saw Iyengar anywhere in the bazaar, that was enough: the children would slip into a side lane out of fear so that he would not see them. He noticed this. One day he wrongly supposed that I too had seen him and slipped away.