1 & 2 Samuel reflect two sides of a promise — the promise to David that he would be king over Israel. In 1 Samuel David is waiting for that promise to be fulfilled. In 2 Samuel the promise is fulfilled.
In the book of 1 Samuel records three “tectonic shifts” in how God structures His kingdom. These three shifts are to prepare the way for the next major shift: transforming God’s people from with a geopolitical identity to a people with a heavenly identity.