The faculty that leads a person through the wilderness cannot itself enter the promised state. Moses is the drawn-out reasoning mind, the deliverer who guides the assembled powers across the desert of purification but stops short of the goal, because leading is not the same as arriving. His failure of trust at the water bars him from the land: the mind that conducts the work is not the part that completes it.
The land given is the settled inner ground of realization, and the congregation is the whole company of a person's faculties brought toward it. Aaron, the voice that speaks for the mind, shares the same limit. What reads as a leader's punishment is the truth that the reasoning self, for all its guiding, is laid down at the border while consciousness passes into the promise beyond.
Moses: the drawn-out reasoning mind, the deliverer that guides the inner powers yet cannot enter the goal
Aaron: the speaking voice of the mind, sharing the same limit as the reason it serves
The congregation: the whole assembled company of a person's faculties led toward realization
The land: the settled inner ground of realization, the promised state consciousness is moving toward