Midrash Rabah, “Devarim,” 04:1 – 04:2: Moses asked, “Allow me to repeat Torah from the beginning to the Jews before my death! I want to explain to them all difficult places and details of the laws of the Torah!”
Moses can’t enter the land of Israel because we enter it in order to conquer it, and Moses is on the level of pure Bina, absolute bestowal. Therefore, all his work ends in the interval from Egypt to the receiving of the Torah and its development.
The sons of Israel passed the first period of learning the Torah and its adaptation while wandering in the desert for forty years. They die during these years, meaning all the egoism with which they exited Egypt dies in them and gets fully corrected to bestowal.
Now they need to work with this quality in order not just to rise above all egoistic desires but to convert them into altruistic ones. Like a farmer in ploughing the earth, turns it over, allowing new shoots to come up, the same thing happens here.
And Moses is not ready for this. This isn’t his force, but the use of the lower egoistic quality, of the land of Israel that isn’t the land of Israel yet. It will become the land of Israel once it is conquered.
From KabTV’s “Secrets of the Eternal Book” 1/20/16