Okay kiddo, do you remember Peter, one of Jesus' very close friends and disciples? Well, one day, Jesus asked Peter and the other disciples, "Who do you think I am?" Most of them gave different answers, but Peter said, "You are the Messiah, the Son of the living God!"
Jesus was very pleased with Peter's answer and told him that he was blessed by God for knowing this. This moment when Peter recognized Jesus as the Son of God is called the Confession of Peter.
It's kind of like when you learn something new or figure something out that you didn't know before. When Peter declared that Jesus was the Messiah, it was like he suddenly understood something very important and was proud to share it with everyone.
So the Confession of Peter is a really important moment in the Bible because it shows us that Peter understood who Jesus was and believed in him, even when others were unsure.