Fighting slavery has become a popular cause in the United States. People of all ages, political parties, and religions came to the third annual Stop Modern Slavery Walk in Washington, D.C. on Saturday. The 5K walk started at the Constitution Gardens, and threaded past the Lincoln Monument and new Martin Luther King, Jr. memorial.

Jostling through the crowd of walkers, I saw signs with statistics on human trafficking, others plastered with pictures of child slaves. Their faces were somber, pained, and silent. "Twenty-seven million people are slaves!" some marchers shouted to passing cars. I passed a young man in a Lincoln costume carrying a sign that said, "Real men don't buy sex."

The face of the young sex slave appeals to our emotional sympathies. As Meagan Clark, one of the walk's organizers, told me, "This is a cause we can personally connect with."

But to what extent can wealthy, comfortable Americans "personally connect with" the pain and suffering of a sex slave or exploited worker? To us, "27 million" is just a number. Those haunting faces are just pictures on a piece of poster board. We do not know that slave girl's name, or her favorite color. Most of us have yet to tangibly love these abused and broken individuals.

A few have, however. Cheryl and her husband Robert were among those strolling quietly along Independence Avenue, among walkers wearing red "Join the Movement" shirts.

They had just returned from Kuwait, they told me, where Robert was stationed at the Philippine embassy. Some years ago Cheryl had read of human trafficking and the enslavement of innocent women, and her heart burned with a desire to help. But without necessary qualifications, anti-slavery nonprofits rejected her help. Carrying the weight of her unfulfilled dream, she prayed, "Why God, when none want what I have to offer, would you plant this desire inside my breast?"

Then in Kuwait, Cheryl discovered the embassy's shelter for women. It was filled with victims of domestic trafficking, who were scarred by physical and sexual abuse. She wondered if this was the opportunity she had been praying for.

"I believe I have found my place here; I felt so drawn to these beautiful girls and ladies who have suffered so much pain and injustice," she wrote on her blog in 2009.

Over the next two years, Cheryl built a program called "Trash to Treasures," helping the women make rugs out of discarded fabric scraps. The shelter was overcrowded and dirty, but with effort and time, it became a clean and orderly space.

There was light in her eyes, joy in her voice as she described the shelter. Now back in the United States, she has not forgotten them. Her fight against injustice does not begin, or end, with a 5K walk.

"My spirit is boiling, heat rising, a crescendo of anger at the injustice I see," Cheryl wrote in March about the abuse of local housemaids. "The fury spills down my cheeks unchecked. Perhaps these tears belong to God himself."

In America, it is easy for us to walk 3.1 miles for freedom. Injustice and slavery are "issues" we want to fix, numbers we want to change. But the face of each slave is an individual life-with scars and joys, fears and failures. It represents a sinful, stained, but beautiful person: a person indelibly stamped with the image of God.

For Abraham Lincoln and Martin Luther King, Jr., injustice was not something to be fought on a clear Saturday morning in October. It was not a cause that could be plastered on a sign, a statistic that could be shouted at passing cars, a temporary break from the normal schedule of life. King once said, "Justice at its best is love correcting everything that stands against love."

Twelve years from now, I hope the 15th annual Stop Modern Slavery Walk will fill the streets of Washington, D.C. I hope thousands will call for freedom and justice. But after meeting Cheryl, I would be ashamed to simply walk. I want to serve and love in a tangible way-to meet the girl on the sign.