Matthew 7:26

And everyone that heareth these words of mine, and doeth them not, shalt be likened unto a foolish man, who built his house upon the sand: and the rain descended, the floods came, and the winds blew, and smote upon that house; and it fell: and great was the fall thereof.

All this is a recapitulation, in the negative, of what was said immediately before. The focus of attention here should be upon the revelation of what the true rock actually is, namely, the words or teachings of Christ. This is the point so many seem to miss.