Joshua - Chapter 22

In verse 5 we read:

"take careful heed to do the commandment and the law which Moses the servant of the Lord commanded you, to love the Lord your God, to walk in all His ways, to keep His commandments, to hold fast to Him, and to serve Him with all your heart and with all your soul."

This is a reminder of Moses' words in Deuteronomy 6:5: "You shall love the Lord your God with all your heart, with all your soul, and with all your strength."  These words were quoted by Jesus (in Matthew 22) when he was asked which was the greatest commandment in the law.