The New Covenant Sprang Forth From the Old Covenant
Moses led the people well, but he couldn’t lead the people into the Promised Land. It was never his destiny. He was merely supposed to show the people what could be possible and what was just beyond the horizon. His story personifies the Old Testament.
Joshua, however, was the only one able to lead the people into the land flowing with milk and honey. His story personifies the New Testament, and more importantly, what Jesus did for all of us. Only Jesus Christ (of which Joshua was a “type”) can lead us into the Promised Land.
Moses symbolizes the Old Covenant that pointed, and ultimately gave way to, the New Covenant. The Old Covenant was not done away with because it still exists to this day. It simply requires the correct Guide to lead the people.