Okay kiddo, have you ever heard of a family tree? It's like a big chart that shows all the people in your family, going back a really long time. The Tree of Jesse is a special family tree that shows the ancestors of Jesus, who was a really important person in history.
You see, a long time ago, a man named Jesse was the father of a man named David. David was a king in a place called Israel, and he was really important to the Jewish people. They believed that someday, a special person would come from David's family who would save them and be a great leader.
So years and years later, when Jesus was born, people realized that he came from David's family! And that's why they made the Tree of Jesse - it shows all the people who came before Jesus in his family line. It's like a way to remember where Jesus came from and how important he is to people all over the world.