Okay kiddo, so the penitential psalms are a group of seven psalms in the Bible that people have used for thousands of years to say sorry to God for things they have done wrong. These psalms are like special prayers that ask for forgiveness and show that we are truly sorry for hurting others or not following the rules that God wants us to follow.
The seven psalms are called Penitential Psalms because "penitential" means something that helps us feel sorry for something we have done. Each Psalm has its own special message, but they all have a common theme of asking for forgiveness and showing repentance for any wrongs we have done.
These psalms are often used during religious services and times of personal prayer as a way to reflect on our actions and ask for forgiveness. They are important because they remind us that we all make mistakes and that it's okay to admit when we've done something wrong.
So, when we say these psalms, we are saying to God, "I'm sorry for what I did, and I want to make things right." And God, being loving and forgiving, will help us find ways to make things right with the people we hurt and with Him.