Today's Gospel is selected from the end of Jesus' Sermon on the Mount. Jesus rounds up His teaching by reminding us that His Gospel demands action in our lives. His images of building on solid rock and on sand complete his teaching by reminding us of several truths. First of all, it is possible, with God's grace, to build our lives on a solid foundation. The teaching of Jesus, what he calls "my words", provides us with that solid foundation, because they reveal to us the will of our Father in heaven. Secondly, the enterprise of building a house requires a preliminary testing of the ground to determine whether it is suitable or not, whether it is rock or sand. So, in the same way, we must reflect on the foundation of our lives: how truly do we accept our faith? How sincerely do we accept Jesus as our Saviour? Thirdly, building a house is no small enterprise: it requires much labour and no little cost. Following Jesus requires an effort on our part: Jesus often refers to this effort as "carrying the cross". There is a cost to discipleship.