The practicalities of how Galilee is physically situated shed interesting light on this parable. Martin's comments make me think about how this also ties in with Jesus' previous words cautioning against taking "the broad and easy way."
24 ... The Greek word for wise could also be translated as "prudent" (see 24:45); this man's prudence lay in his choice of a site to build his house (real estate has always been a matter of location, location, location). Galilee is dotted with limestone hills covered by an uneven layer of soil. Houses commonly had stone walls; an outcropping of rock provided a stable base for such walls. This wise builder picked a site where he could build his house on rock.My review is here of Bringing the Gospel of Matthew to Life by George Martin.
25 The rain fell, the floods came, and the winds blew and buffeted the house. But it did not collapse; it had been set solidly on rock. The rocky hills of Galilee do not readily absorb rain; a heavy rainfall can become a flood of water crashing down hillsides and filling ravines. A stone house built on rock can withstand floods and windstorms.
Jesus says that those who listen to his teachings and act on them, "will be like" (verse 24) a wise builder whose house withstands a storm; the phrase "will be like" points to something that will happen in the future. Prophets used storms as an image for God's judgment (Isaiah 28:2; 29:6); 30:30; Exek 13:10-16). Jesus is again speaking of the last judgment (see verses 13-14, 19, 21-23), now by means of a comparison or parable. Those who take Jesus' words to heart and act on them will withstand God's judgment, just as a house built on rock withstands a storm.
26 And everyone who listens to these words of mine but does not act on them will be like a fool who built his house on sand. Rain flushed soil and sand down from hills to the floors of valleys and ravines, providing some temptingly level places to build a house. A foolish builder might choose such a site, laying the lowest course of house walls directly on sand.
27 The rain fell, the floods came, and the winds blew and buffeted the house. Storm runoff surged against the house, washing way the sand beneath its walls and undermining them, and the house collapsed and was completely ruined. Just as a house built on sand will collapse in a flood so those who do not live according to Jesus' teachings will face utter ruin at the last judgment.
For reflection: Upon what am I basing my life?