Foundational Truth
Construction workers know the importance of foundations. It is not the structures we see above ground which determine their lasting value, but what is unseen. Jesus used this building illustration to challenge religious leaders and alert His trainee apostles to a new way of living. They were used to seeing so-called 'holy' people paraded in public, but what were their hearts like, deep down? Jesus said that His gospel words alone had the power to change people from the inside, so that their lives would be unshakable (1 Corinthians 3:11).
The disciples had started to follow Jesus by obeying His words (Luke 6:13), and there was no other way to continue if they were to remain secure (John 6:66-68). But one of them, Judas Iscariot, ignored Jesus: he sadly proved the truth of this parable by building his life on the 'sand' of money and greed, leading to his destruction (John 6:70). So, although Jesus provides the only safe foundation for a secure life with God, disaster will still come unless we are willing to obey Him. His building-site example gives no room for misunderstanding - build your life on the Lord Jesus Christ or face disaster (Luke 13:4-5).
Believing in Jesus (that means obeying His words) does not stop the storms; these will inevitably come, testing the foundations of every person's life. But having started with Him, we must keep on obeying Him - if we fail to do so, the cracks will certainly appear. Christians are often tempted to desert the grace of Christ (Galatians 1:6-7) by believing in the security of money, possessions, status, ideas, self-discipline or family solidarity; or even the approval of religious people. None of these will enable us to pass the test of death, and all will fail to deliver peace with God.
Jesus alone has the power to make us peacefully productive in this life, and gives us confidence of His welcome into the life to come. So ... as His mother Mary said, "Do whatever He tells you" (John 2:5).