Jesus exposes a gap between words and life. His hearers called Him "Lord, Lord," but did not do what He said. Gill says they were "acknowledging, in words, his government over them," and that "such words in their mouths would be of no use to them" without obedience. Barnes, whose note on this verse points to Matthew 7:21-27, teaches there that a mere profession of His name will not gain entrance to the kingdom. Matthew Henry turns the question on every believer: why call Him Lord in prayer if we do not obey His commands?

Jesus answers with a picture. Whoever "heareth my sayings, and doeth them" is like a man who "digged deep, and laid the foundation on a rock," and when the flood came the stream "could not shake it" (Luke 6:47-48). But whoever "heareth, and doeth not" built "without a foundation," and "immediately it fell; and the ruin of that house was great" (Luke 6:49).

Matthew places this teaching at the close of the Sermon on the Mount, where it is sharper still: "Not every one that saith unto me, Lord, Lord, shall enter into the kingdom of heaven" (Matthew 7:21). There, some will say, "Lord, Lord, have we not prophesied in thy name?" and hear, "I never knew you" (Matthew 7:22-23). Barnes notes on that passage that even miraculous power is no proof of true faith, for "God may as well, if he chooses, give the power of raising the dead to a wicked man, as the skill of healing to a wicked physician."

In Luke's version, the difference between the houses is not the storm, which strikes both, but the foundation. One builder "digged deep" to rock; the other built "upon the earth" (Luke 6:48-49).

This question shows how Jesus understood Himself. He expects His own sayings to be the foundation of a life: "Whosoever cometh to me, and heareth my sayings, and doeth them" (Luke 6:47). He speaks as a Lord whose word is to be done, and He accepts the title while asking that it be meant.

Matthew Henry writes that "those only make sure work for their souls and eternity" who not only come to Christ and hear His sayings but do them. Jesus is not asking for more impressive words. He is asking for lives built on what He says.