In his book, “The Waters of Siloe,” Thomas Merton tells the true story of a French businessman in the months after World War II. The businessman had been born and raised Catholic. But he’d forgotten about his faith has he got older.

During a business trip, he was checking into a Paris hotel late one night. As he passed through the lobby, he saw a young nun, alone, who just looked at him and smiled. He tipped his hat as he passed and went to the desk to sign in and asked the clerk, “Who was that nun?”

The clerk said, “What nun?”

And the businessman turned around and noticed that she was gone.

“She was just there,” he said. “She went by and smiled at me.”

The clerk said, “You must be mistaken. Nuns don’t go around at this hour of the night smiling at men.” And then he added, “Monsieur, you are the only one who has been in the lobby in the last hour.”

A few days later, while still in Paris, the businessman had dinner at the home of some friends, and noticed on the mantle a small picture. He went over and took a closer look. It was the very nun he had seen in the lobby a few days before.

“Who is that?,” he asked. And he was told: “That’s St. Therese of the Child Jesus…Therese of Lisieux.”

Not long after that, the businessman went back to church. He began to pray again. He returned to the faith that he had abandoned so many years before. And in a matter of months, he gave up the Paris hotels and expense accounts and silk suits…and lived in a simple brown robe, fixing tractors and tending cattle at a Trappist monastery in France.

You’d be hard pressed to find a more remarkable conversion. And it’s one worth sharing and remembering as we approach St. Therese’s feast on Wednesday, October 1st.

Conversion in one way or another is at the center of this Sunday’s readings. The scripture calls us to repentance, to change. God asks us to redirect our lives. Ezekial writes of “turning away from wickedness.”

And St. Paul points the way.

“Do nothing out of selfishness or vainglory,” he writes. “Rather, humbly regard others as more important than yourselves…each looking out not for his own interests, but also for those of others.”

Make yourselves, he writes, like Christ. That, of course, is the very essence of what we are meant to be. That is what it means to be Christian. But how many of us truly live up to the job description? We hear the gospel every Sunday. We receive the message. And so often, it’s gone by the time we hit the parking lot.

But in Matthew’s gospel this Sunday, Jesus summons his followers to something better than that. Tax collectors and prostitutes, he tells them, are changing their ways. They’re – in effect — working in the vineyard. Why aren’t you?

We could all ask ourselves: why aren’t we?

I had lunch recently with a friend who had attended World Youth Day in Sydney, and he told me about something one of the bishops said in a homily. “All of us have one thing in common,” he said, “including me. We all have something keeping us from committing totally to Christ. What is it?”

It’s a challenging question. Answering it may tell us more than we really want to know about ourselves. But it can leave us changed. And it can change those around us as well.

Consider the story of Thomas Merton. His conversion story is one of the most famous in the American church. And it affected countless people, even to this day. Merton spent a number of years living in Douglaston, taking the Long Island Rail Road into the city. He was a cigarette-smoking, jazz-loving, girl-chasing poet and struggling novelist who, while working on his master’s at Columbia, found himself drawn to the Catholic Church. He was baptized in 1939, and two years later gave up everything he had to become a Trappist monk at a monastery in Kentucky. In 1949, he wrote his autobiography, “The Seven Storey Mountain.” It became a bestseller and prompted thousands of vocations. 50 years later, one of the vocations it helped inspire was my own.

Conversion isn’t a one-time event. It isn’t a moment. It is thousands of moments. It is a lifetime of moments. And it never ends. When he became a monk, Merton took a vow of “conversatio morum,” conversion of life. It means a total re-orientation of who you are and how you live – turning continually toward God, and allowing God to work in you and on you and through you. It is learning to love, truly love.

Loving, and growing in love, is part of our lives as Catholic Christians – part of our own ongoing conversion in each. The effort is unceasing.

When I was in high school, one of my teachers used to wear a pin that said, “Please be patient, God isn’t finished with me yet.”

It’s true. He isn’t. God isn’t finished with any of us. But he asks us to work with Him, to collaborate with Him.

He invites us to be a part of His great work – calling us to be like Christ.

The call may come in ways we never expect – through people we never imagined we’d meet in a hotel lobby. Or it may come in a more ordinary way, in a quiet voice that speaks to the heart.

As the gospel reminds us today, the invitation is open. The opportunity is always there.

My friends, the vineyard is waiting for us.

What are we waiting for?