What is so bad about being an "Am Keshei Oref"? Why does it negate the merit of inheriting Eretz Yisrael?
Seforno: Because a person who is stiff-necked sees only what he wants to see, and is incapable of turning his head to see what others show him, even when wise men show him that he is heading towards his own destruction. Consequently, his decisions cannot possibly be just and correct. 1