Joshua gives a summary of the history of Israel, emphasizing God’s faithfulness toward the people and their forefathers. He then asks if they intend to live as God has told them to do. They strongly agree to follow God.
Remembering God’s faithfulness to us and committing to following him is what baptism and communion are about. We can do this in other ways too, like telling someone our story of how we came to Christ. When was the last time you told someone your story?