One of the most basic recurring themes in Sacred Scripture is "Don't forget what God has done for you and your ancestors!"
The first half of chapter 24 of Joshua is a quick summary of salvation history from the time of Abraham (chapters 12-24 of Genesis) to the end of the Book of Joshua. By presenting this overview of God's continuous intervention on behalf of His chosen people, Joshua hopes to inspire the people to respond by whole-heartedly choosing God (that choice, and the Israelites' response, will be presented in tomorrow's reading of the second half of Joshua 24).
By now, it should be apparent that one of the most basic recurring themes in Sacred Scripture is "Don't forget what God has done for you and your ancestors!" Most of us are probably guilty of not thanking God enough for the many blessings we've received from Him in our own lives, but all of us are certainly neglectful too often of thanking God for the blessings He's given to those who came before us - all that we've spiritually inherited should certainly inspire us to turn in gratitude to Him through whom all blessings come...