Answer: Because they already have the impression of how scary it is and now they have to work with this impression. The forty years of wandering in the desert begin at this point because the basis for that already appears in them.
They didn’t have it before that, so why should they wander? If the Creator only wants to confuse or to kill the older generation, He could do it now at one time.
But the point is not for Him to kill the older level but for us to kill it. What does it mean that the older generation dies? It means that our old perspective of the world, of ourselves, of the decisions we should make, and of our understanding of the land of Israel dies in us. We gradually wash the old paradigm away and are included in a new one. This is the only way!
Question: The nation of Israel complain in the desert that they don’t have food and water, but when they get closer to the Promised Land they begin to complain that they cannot enter it. What is the difference?
Answer: If the nation first complained on a corporeal level, now they complain on the level of doubting the Creator’s help. This means that if you annul yourself with regard to the next level, if you close your eyes and follow the Creator, all the obstacles disappear and you enter the land of Israel. But in order to do so you have to suppress your ego and advance above it in faith above reason.
From KabTV’s “Secrets of the Eternal Book” 5/6/15