Today, Rev. Joshua Patty preached about the book of Deuteronomy, the last of Torah, the first five books of the Bible. In some ways, Deuteronomy simply retells parts of the story of Exodus. However, while Exodus focuses on God's miracles which freed the Israelites from slavery, Deuteronomy is much more concerned with how the Israelites should learn to treat God before they enter the Promised Land.
Perhaps the most famous passage of the book was quoted by Jesus, when God expresses the desire that all of the people will "love the Lord your God with all your heart, and with all your soul, and with all your might." This passage goes on to explain why God desires such faithfulness -- because once they enter the Promised Land, they will claim cities they did not build and drink from wells they did not dig and God worries that they will forget God's part in bringing them from slavery to freedom. If this happens (as indeed, it eventually did in Jewish history), the people will also begin to treat others around them badly. Instead, God hopes that by keeping a good relationship with the Lord their God, they will also treat others around them well -- an important final lesson before they cross the Jordan and enter the Promised Land.
You can listen to the sermon here.
You may also be interested in the related closing benediction.