Whenever I'm at the beach, my favorite time of the day is early evening, walking the beach, very often as the tides are receding. And as I walk, I often find remnants and ruins of sand castles, some that look to have been very impressive. I often wonder how many hours were put into building the castles; most often by laughing children, sometimes by entire families carrying water and dripping wet sand to make pointed peaks on the towers. Sometimes I find a half-buried shovel left behind, used to dig a deep moat around the walls of the castle.

I suspect many of us have been one of those laughing children, or one of those adults covered with sand, arguing as to how big the castle ought to be, how many towers, how deep the moat, digging the sand and trying to avoid the incoming waves.

And, I suspect, many of us have also been the ones walking the beach in the evening or early morning, recognizing a crumbling wall, or a ruined tower, noticing that sand castles are no match against the force of the water and the intensity of the waves.

A few years ago when my wife and I were in California, on our final day there we drove to Laguna Beach. You might remember it was there where lots of homes are built over-looking the Pacific Ocean, and several homes slid off the hillside into the ocean because the foundations were not constructed to withstand the weather conditions in that town. Ruined castles in the sand and crumbled homes at Laguna Beach both serve as glaring visual reminders of the image used in today's Gospel, as to the importance of, not only hearing God's word, but also acting upon it.

These verses as we hear them today are the conclusion to the Sermon on the Mount. The Sermon of the Mount, as we know it, encompasses Chapters 5-6-7 of Matthew's Gospel. It begins with the Beatitudes, including such sayings as "You are the salt of the earth," "You are the light of the world." We hear a reinterpretation of the 10 Commandments, where we are charged "to love our enemies and pray for our persecutors." We are given the Lord's Prayer, asked to pray without making a "big deal" about it. We are challenged to live life with sensitivity to the ever-present relationship of God in our daily relationships with each other.

So when we get to the very end of this three-chapter Sermon, we hear Jesus say, "I've just given you lots of ways of living that usher in the Kingdom of God in our midst, into our world. You've heard my words, but now it is up to you because if you hear, but do not act, your lives are no different than ruined sand castles that wash away at high tide, or Laguna Beach homes sliding off the mountainside."

The advertising slogan for "Nike" - Just Do It - might be the best sermon title for Jesus' Sermon on the Mount. Hearing is not enough; hearing must bear fruit in action: Just Do It!