It is part of the refining/sifting process ("I will sift you as wheat" [getting rid of the chaff - and leaving the tares in the field to be burned]). Here is a great quote to back this up:
One of the quotations I hear frequently repeated is part of a sermon by Joseph F. Smith in 1882: “When God leads the people back to Jackson County, how will he do it? Let me picture to you how some of us may be gathered and led to Jackson County. I think I see two or three hundred thousand people wending their way across the great plain enduring the nameless hardships of the journey, herding and guarding their cattle by day and by night. … This is one way to look at it. It is certainly a practical view. Some might ask, what will become of the railroads? I fear that the sifting process would be insufficient were we to travel by railroads.” (Journal of Discourses, 24:156–57.)
Have good hiking shoes that are broken in (or lots of blistex and mole skin.....).