“. . . and great was its fall . . .”
I have heard a lot of different opinions as to exactly how best to understand Christ's parable of the wise and foolish builders in Matthew 7. I can appreciate different perspectives as to exactly what might be meant by the rock, the sand or the wind, but I don't know if this is entirely the point of Christ's illustration.
I have a tiny, inexpensive house. It is the least expensive house of which I know. But even though it is small and cheap, I know that should this house crumble it is a big deal. People might die. Authorities need to get involved. Roads would be closed, weekends would be ruined, finances would be drained, lives would be changed forever. And this is the smallest and cheapest of homes.
The Sermon on the Mount records some of the greatest teachings ever recorded. Christ ends this instruction by indicating just how important this teaching is. Understanding and following Christ's teaching as recorded in the Sermon of the Mount is the difference between everything.