A family in White Russia were once having trouble with their young son, Mordechai. He never wanted to study, only to play outside. He also had a tendency to get into mischief. It caused the parents tremendous anxiety.

One day they heard that the great R' Aharon of Karlin would be coming to their town. So they brought their son to meet the Rebbe. He listened to the parents story and responded to them very roughly. "I'll have a few words with him and set him straight. Leave him to me. I'll teach how to behave." The parents, taken aback by his stern demeanor, yet assured by his confidence, let him take their son into his private room.

The Rebbe leaned back on his couch and gently called the boy to come over. He held out his arms and motioned for Mordechai to come nearer. Then he pulled him close and held him against his heart for a long time. They then went out together. Not revealing his special method of persuasion, Reb Aharon of Karlin again spoke roughly to the parents. "I had a word with him. He'll shape up now!"

The boy did indeed change and became a well-known tzaddik, R' Mordechai of Lecovitz, the father of the Slonim dynasty. He always told his chassidim that he first learned Torah from R' Aharon of Karlin, who taught him Torah from the heart.