The Gospel reading reminds us that false leadership can emerge in the service of the Kingdom. There will be those claiming all kinds of power or of doing many things in Jesus' name for their own name's sake or for self-glory. However, since only those who do the will of the heavenly Father will enter the Kingdom, the claims of these leaders are also false. They may be performing many mighty works in Jesus' name but are not living a life of true discipleship. On the day of judgement, Jesus will declare to them "I never knew you."
In his sermon, Jesus tells the people that when we build our house on sand, it is like building our faith on false leadership and false claims. This type of faith will not last. Instead, to build our house on a rock, means to "to build one's life on God," since God is Himself is "the Rock". Here, Jesus recalls the covenant relationship established by God with the people of Israel at Sinai. Regardless of all that had happened in the history of Israel, God has always remained faithful to the covenant.
We should avoid false leadership or claims that seek to lead us closer, not to God, but to the leader himself or herself. Our call as disciples is to do God's will and to constantly build on the covenant relationship between God and us. A life build on this covenant relationship with God cannot fall, no matter how strong the forces against it.
Lord, help me build my trust in You alone.