When reading the Old Testament, it becomes quickly obvious that this is more a story about God than about people like Moses, Abraham, and David. That said, the people of God need to tell their stories for that very reason! Just as in the Old Testament, when the stories of God's people are told in light of the larger story God is writing, these stories become a testimony to the Gospel "good news" of God.
Who is God? Who am I? Why are we here and what is possible? How do I make sense of this life... its joys, challenges, purpose, etc? How are we to relate to one another... the world around us... creation... ?
Life is full of questions and challenges, and God's people have forever been encouraged to tell their story in answer to them. In Joshua 4 God parts the Jordon river, and the people of God cross over into the promise land on dry land. As they cross over God has Israel's leaders take up 12 stones from the riverbed that Joshua uses to build a memorial. God explains His purposes to Joshua saying:
"this may be a sign among you. When your children ask in time to come, 'What do those stones mean to you?' then you shall tell them that the waters of the Jordon were cut off before the ark of the covenant of the Lord. When it passed over the Jordan, the waters of the Jordan were cut off. So these stones shall be to the people of Israel a memorial forever." Joshua 4.6-7
"When your children ask.... then you shall tell them." The gospel is REALLY good news, but it is a story that must be shared. It is in the telling that we are reminded we are a part of God's story and the next generation find their place in that same story.