Washington — With the passing of Jean Vanier on May 7, the sum of the world’s welcoming kindness diminished appreciably.

More than 50 years ago, Vanier sparked an unlikely movement of conscience. Shocked by the despair and loneliness he found at a psychiatric hospital outside Paris, Vanier did not merely adopt the cause of the intellectually disabled; he decided to buy a dilapidated house and live with Raphael Simi and Philippe Seux, two people with severe intellectual disabilities. “Essentially, they wanted a friend,” Vanier said. “They were not very interested in my knowledge or my ability to do things, but rather they needed my heart and my being.”

This highly personalized model of compassion now inspires 10,000 people who live together in more than 150 L’Arche group homes around the world. Those without intellectual disabilities — known as “assistants” — spend a year or more committed to a L’Arche home and its disabled members. And the relationship can be transforming for both.

When you visit one of these L’Arche communities, you are immediately impressed by the rigor and order of the average day. Chores and work schedules are taken seriously. But so are affirming celebrations such as birthdays and rituals such as communal meals and prayer. These homes offer safety, routine and acceptance. And people with disabilities often respond by showing unsuspected aptitudes for friendship and love.

The L’Arche movement is not sectarian, but it is clearly informed by Vanier’s Catholic faith. His life’s work reflects a Christian anthropology — a belief in the inherent rights and dignity of every human life. Vanier identified this as “the belief in the inner beauty of each and every human being.”

In one sense, Vanier’s approach to compassion is wildly inefficient. Who would design a social program that strives for a one-to-one ratio of helpers to helped? How could that type of effort possibly be scaled? But that is precisely the point. L’Arche is not a traditional social program. Its commitment to the dignity of people with intellectual disabilities is lavish, extravagant. It rejects a utilitarian cost-benefit analysis. And it certainly rejects a Social Darwinism that views the vulnerable as worthless. By serving a group of human beings that others ignore or discount, Vanier made the case that no human being should be ignored or discounted.

Vanier’s radical Christianity goes even a step further. Not only are the disabled inherently valuable, they have much to teach us. “It has been this life together that has helped me become more human,” Vanier reflected. “Those I have lived with have helped me to recognize and accept my own weaknesses and vulnerability. I no longer have to pretend I am strong or clever or better than others. I am like everybody else, with my fragilities and my gifts.”

As a teacher and writer, Vanier spoke to a broader cultural unease. In modern societies, it is not only the disabled who feel isolated, abandoned and alone. Vanier diagnosed loneliness as the great challenge of our time. “Loneliness is a feeling of being guilty,” he said. “Of what? Of existing? Of being judged? By whom? We do not know. Loneliness is a taste of death.”

The answer to loneliness is the same thing that L’Arche offers. Human beings can only thrive and be happy in small, family-sized communities. And communities of this type are only created through mutual vulnerability. And that sense of vulnerability requires a knowledge of our frailties. And so the happiness and belonging we need most in life begin with a recognition of our own weakness.

“If we deny our weakness and the reality of death,” Vanier wrote, “if we want to be powerful and strong always, we deny a part of our being, we live an illusion. To be human is to accept who we are, this mixture of strength and weakness. To be human is to accept and love others just as they are. To be human is to be bonded together, each with our weaknesses and strengths, because we need each other. Weakness, recognized, accepted and offered, is at the heart of belonging.”

Vanier’s message was so different from our typical cultural emphasis on strength and independence. It will be terribly missed. But it is carried forward by the assistants and people with disabilities at L’Arche, who have much to teach us about the universal human need for acceptance and belonging.

— Michael Gerson is a columnist for Washington Post Writers Group.