WASHINGTON -- The elderly black woman began preaching moments after the train left the Capitol South subway station.

"Praise the Lord. It's a good day," she said, starting a 20-minute sermon as her rush-hour congregation rolled toward the Maryland suburbs.

Her voice was calm, strong and serious. She was carrying a cane and, I wouldn't dare make this up this detail, a fragrant box of spicy fried chicken. I didn't take precise notes, but what follows is real close to what she said. My father was a Southern Baptist preacher and I have a knack for remembering sermons.

"God's grace is real, but that doesn't mean you can just keep on sinning and sinning and sinning," she said, gazing straight ahead. "God is watching all the time. God sees all of you. ... Our God is a Holy God."

People kept their eyes down, reading their newspapers and paperbacks. A young black woman across the aisle giggled. "Oh no, it's church," she whispered to a friend. New riders glanced around in surprise, as they boarded the crowded car. But no one challenged the preacher or asked her to stop.

"God doesn't ask that much of us," she said. "He wants us to love each other and take care of each other and follow the commandments that are in His Word. Is that too much to ask?"

A youngster listening to rap on headphones said, "Preach it, sister." Surely the collision between the pounding music and the sermon was causing a storm in her head. At first she was amused. Then she began shooting daggers at the preacher with her eyes.

"I know what you're thinking," said the elderly woman. "You're saying, 'How are we supposed to know how we're supposed to live?' ... You know what the Bible says: 'For God so loved the world, that he sent his only begotten Son, that whosoever believes in him should not perish, but have eternal life.' You all know that verse, right?"

No one answered.

"Sweet Jesus is all the guide we need. But God also gave us his Word. You open up your Bible and read it and tell me that God hasn't made himself perfectly clear how we're supposed to live. The Bible is God's book. There's no other book like it. Some of you may go to church and you may read your Bible. But have you ever let it get inside you and change you? That's what I'm talking about. We've got to change on the inside. We've got to change how we live."

I moved to the Washington, D.C., area six months ago and I have, in that short time, seen many people reading worn-out Bibles on trains. But I think I have seen exactly one white person reading a Bible. I wonder how many white believers ride around in the political capital of the world looking at these faithful black Christians, wondering who they are, why they are marking up their Bibles, what churches they go to and why we seem to live in separate worlds.

Come to think of it, I haven't read my Bible on the Metro either. I wonder what this preacher would think of that? I was reading a stack of religion-news magazines and wearing a cross. I wondered: Was this good, or bad? Was I a fake, to her?

By the time we reached the last station, out by the Beltway, many people had left their seats and were lining up to exit -- even quicker than normal.

The preacher brought her message to a close.

"What I'm saying is that God loves you and sent his Son to die for you. But I know that many of you are not listening," she said, still in her seat. "Maybe one person will go home tonight and think about what I am saying. Maybe God will touch one person's heart and they will go home and talk to their children about Jesus. Maybe one person will pray with their children tonight.

"That's why I'm saying what I'm saying. If one person hears the Word, then this is worth it. Just one person."

She was the last person to leave the train.