12th Sunday after Trinity
Matthew 16:13–20
Firm Foundations
I wonder when you last watched children building sandcastles on a beach?
At first they work with enormous concentration, patting damp sand into buckets, carefully shaping towers and walls, perhaps even digging a little moat around their masterpiece. For a while it looks magnificent, as though it might last forever. Then the tide quietly begins its work. One wave reaches the castle, then another. Before long the towers soften, the walls collapse, and the beach is smooth once more, as though nothing had ever stood there.
Of course, that is part of the delight. Every child knows another castle can be built tomorrow.
Yet it does make me wonder.
What are the foundations that truly last?
What are the things in our lives that remain standing when the tides change, when unexpected waves arrive, when life unfolds differently from what we had imagined? Where do we find solid ground when so much else shifts beneath our feet?
That question lies at the heart of today’s Gospel.
Jesus takes his disciples to Caesarea Philippi and asks them perhaps the most searching question any of us will ever face:
“Who do you say that I am?”
Peter answers with remarkable clarity:
“You are the Messiah, the Son of the living God.”
And Jesus replies:
“You are Peter, and on this rock I will build my Church.”
For centuries Christians have reflected on those words. Is the rock Peter himself? Is it his confession of faith? Is Christ the true foundation? The writer of Matthew’s gospel may well intend us to ponder all of these. Yet perhaps he is also inviting us to ask another question.
What makes our faith resilient?
The remarkable thing is not that Peter is somehow strong enough to become a foundation. In truth, he is anything but. Within moments he misunderstands Jesus. Before long he will deny even knowing him. Peter is courageous one moment and fearful the next; insightful one day and bewildered the next.
In other words, Peter is wonderfully human.
Perhaps that is precisely the point.
Jesus does not choose someone because he is flawless. He chooses someone who is willing to remain in relationship with him. Peter’s faith becomes resilient not because it is perfect, but because it remains open to God’s continuing work. Again and again he allows himself to be forgiven, reshaped and sent out anew.
That offers hope to every one of us.
Perhaps the deepest foundations of faith are not certainty, nor having every doctrine perfectly understood, nor never experiencing doubt. Perhaps they are trust: the quiet willingness to keep returning to Christ, allowing ourselves to be questioned, challenged and transformed.
Notice too that everything begins not with a declaration but with a question.
“Who do people say that I am?”
And then the more personal question:
“But who do you say that I am?”
That question has never gone away. Every generation must answer it afresh. Every disciple, every follower of Christ, discovers that the answer grows deeper over a lifetime. Faith is less about arriving than about continuing the journey, allowing Christ to reveal himself ever more fully.
During a recent Franciscan Peace Pilgrimage, that question seemed to echo in an unexpected place.
Our pilgrims descended the worn stone steps into the ancient crypt beneath Lastingham Church, deep within the North York Moors. Above us stood the Norman church, resting quietly on its grassy knoll, while around us the moorland folded itself protectively around the little village, giving it the feeling of a place set apart. For centuries travellers have found refuge here. Even before one enters the church there is a sense of homecoming, as though the landscape itself has become a prayer.
Then, beneath the church, everything changes.
The light softens. The air cools. Rough stone, worn smooth by centuries of touch and prayer, surrounds you. Silence gathers, not as an emptiness but almost as a presence wrapping itself around those who enter. The crypt feels deeply earthed, embedded in the very ground, hidden yet wonderfully alive. It is as though the whole church draws its strength from this buried heart.
Tradition tells us that Saint Cedd was buried there. For almost fourteen centuries pilgrims, monks, villagers and weary travellers have carried their hopes and fears, their griefs and thanksgivings into that quiet place. Holy Communion is still celebrated there. Generation after generation has whispered the same prayers, sung the same psalms and sought the same God.
The stones have become witnesses.
Not because stone itself is holy, but because countless lives have allowed themselves to be shaped by God’s presence there. Every prayer has become another layer in the life of that place. Every act of worship has left its unseen imprint. The holiness is cumulative, born of centuries of ordinary faithfulness.
Standing there, one begins to understand that foundations are rarely the things we notice first.
The crypt is hidden beneath the church. Yet without it the building above would lose something of its soul. Like the roots of an ancient tree, its deepest strength lies below the surface.
Perhaps this is something of what Jesus is speaking about when he promises to build his Church.
Not first a building of stone, but a people.
Not monuments, but living stones.
Faith is never something we invent by ourselves. We receive it. We are carried by those who have gone before us: parents and grandparents, teachers and friends, priests and spiritual directors, faithful neighbours and quiet saints whose names history has long forgotten, yet whose lives have become part of the foundations beneath our own.
Peter himself would later write that we are being built into “living stones”, forming a spiritual house. The Church is not preserved like a museum, frozen in the past. It is alive. Each generation receives the faith and then becomes part of its foundation for those yet to come.
The Franciscan tradition understands this beautifully. Francis of Assisi never dreamed of creating an institution. He simply wanted to follow Christ. He thought that he had a mission to rebuild the church. But then realised that he needed to restore broken relationships. Peace always began in prayer before it was lived in the world.
Saint Cedd understood the same truth centuries earlier. His ministry crossed boundaries, reconciled divided communities and patiently nurtured Christian life across northern England. Yet his mission, like Francis’, grew from deep contemplation. Lastingham reminds us that authentic mission always rises from hidden depths. The sanctuary is not a place to escape the world but a place to recover the courage to serve it. It replenishes the heart so that we may return with renewed commitment to love, to forgive and to build peace.
The quiet of that ancient crypt also asks searching questions of every pilgrim.
What lies at the hidden centre of my own life?
What do I enshrine there?
Can I dwell peacefully with what I find within?
Does my prayer send me back into the world more compassionate, more generous and more ready to become an instrument of Christ’s peace?
These are not questions for pilgrims alone. They are questions for us all.
Perhaps resilient faith is rather like those ancient foundations beneath Lastingham. Most of them remain unseen. We rarely notice them, yet they quietly carry the weight of everything built above.
Our acts of kindness.
Our worship.
Our courage.
Our hope.
All are sustained by foundations laid long before we arrived.
And now another question gently emerges.
What foundations are we laying for those who will come after us?
Long after we are gone, will someone else find strength because we chose compassion instead of resentment, peace instead of hostility, generosity instead of fear? Will our prayers become part of those unseen foundations beneath another person’s faith, just as countless unknown believers have strengthened ours?
Jesus promises, “I will build my Church.” Notice that he does not ask us to build it for him. Christ remains the builder. Our calling is simply to keep saying yes—to become living stones through whom his love, mercy and peace may find a home in the world.
So perhaps the question we carry into this week is not simply, “Who do you say that I am?”
It is also this:
What are the foundations on which my faith rests?
And perhaps, quietly hidden beneath the ordinary moments of our life, what foundations is Christ building through us for those who will one day walk this way after you?
Image: Iain Macrae, Unsplash.com
