The Song of "It Can't Be Done."

In the parasha, "Shelakh" we see what became our synagogue's logo: the Two Spies carrying the "Eshkol" (cluster of fruit). They saw the "land flowing with milk and honey, and full of enemies. God stated several times in "giving" us "our own land" that it would contain enemies needing to be overcome. Why is God's "gift" He is "giving" to us full of enemies?