Okay kiddo, so you know how some people believe in God, right? Well, Jesus is believed to be the son of God and also a very special person who taught people how to be kind and love one another. When people say "Jesus is Lord," it means they believe that Jesus is the most important and powerful person in their life and they try to follow his teachings. It's kind of like having a superhero that you look up to and want to be like when you grow up. Does that make sense, little one?