The Wilderness Before the Commission

From Moses, to King David, to the prophets, to the children of Israel, to the disciples, to Jesus himself...all of these are examples that the wilderness comes before the fulfillment of our destiny. Moses did his time as "an alien in a foreign land," (Gen.2:22), David spent time in the wilderness at the cave of Adullum (1 Sam. 21-22), the prophets all had their moments of exile and preparation, the children of Israel spent their 40 years meandering around the desert, the disciples had their moment from the crucifixion of our Lord to the day of Pentecost, and Jesus even spent time in isolation in Nazareth and in the wilderness before He set out to save the world. So, what is it about the wilderness that is so beneficial?
Here are some facts that I have learned and reasons that I believe God sends us to the wilderness preceding a great work for His Kingdom.
1. Isolation.
When we are alone, we are faced with the reality of ourselves. Point fingers all you want, sooner or later you'll have to examine yourself. Isolation also diffuses all other voices and brings clarity of and focus on God's voice alone.
2. God takes illegitimacy and makes it legitimate.
3. Preparation for the magnitude of the call.
The bigger the job, the more materials, skills, and drive it will take to effectively complete it.
4. Desire
We always want the things we can't have, and we always take care of the things we have to work for.

That's just a few raw thoughts off the top of my head. If I think of any more I will be sure to list them. Hope it helps!