“Therefore whoever hears these sayings of Mine, and does them, I will liken him to a wise man who built his house on the rock: and the rain descended, the floods came, and the winds blew and beat on that house; and it did not fall, for it was founded on the rock.“But everyone who hears these sayings of Mine, and does not do them, will be like a foolish man who built his house on the sand: and the rain descended, the floods came, and the winds blew and beat on that house; and it fell. And great was its fall.”
-- Matthew 7:24-27
I always wondered about this comparison, I grew up where the red clay met the sandhills and I noted that very few have the opportunity to literally build their house on a rock. There were thousands built on sand that stood for decade after decade with almost no change but those built on the red clay sometimes settled and shifted, the sand seemed to be the more stable of the two. I guess it depends on what kind of sand it is and how dry or wet. We had a lot of dirt roads and we drove the sand roads in wet weather and the clay roads in dry weather. When it was really dry the sand roads could become impassable, same thing with the clay when it was wet.