Joshua is a story of conquest and fulfillment of promises for the people of God. The promise originally was to Abraham back in Genesis 15, when Abraham didn’t have any sons or hope of any sons. God told him in a dream that his descendants would travel to a strange land, where they would be slaves for 400 years. Then God would punish the slave-holders, and Abraham’s descendants would leave that land, taking great wealth with them. God said that after Abraham’s great-great-grandchildren were born that his people would return to the Promised Land. God said, “I will give to your descendants the land between the river of Egypt and the great river Euphrates.”
So, it took 400 years (to us who count time) but God kept His promise. God promised Joshua that He would be with him and never leave him or forsake him. God has also kept His promise to us with Jesus—who willingly took all our sins upon himself so that we might have a path to fellowship and eternity with Almighty God. But God expects us, as well as Joshua, to remember the Book of Teachings by meditating on it day and night and being obedient to its teachings. In the neighborhood of two thousand and fifty years after Jesus, that promise is still available to you and me, because our God keeps His promises.