The image of a rock is often used in the Old Testament (Deuteronomy, Psalms, Isaiah) to speak of God's steadfastness, reliability, and strength. One can get a profound sense of the appropriateness of this reference touring the Black Hills of South Dakota, viewing the two and a half billion-year-old granite monoliths erupting all throughout the hills, standing bold and undaunted over the Ponderosa pine forests. Mount Rushmore is carved out of one of these -- the faces of four American presidents who spoke guiding words at critical times in our history.