Mendel Wilhelm comes from a Crown Heights Lubavitch family. During the school year, he studies in Brooklyn. This July, he chose to join two dozen other students his age at a six-week summer yeshiva program run by Rabbi Moshe Wilhelm, who is both Mendel’s uncle and the Chabad director in Portland, Oregon.

It’s Friday afternoon, which to a Lubavitch kid means it’s time for mivtzoim, or “campaigning.” Lubavitch schools typically end for the week by noon Friday, releasing students for an afternoon of street outreach. Beginning right after their Bar Mitzvah, Lubavitch boys tramp through city streets and office buildings every Friday afternoon, looking for Jewish men they can persuade to put on tefillin, or phylacteries, the pair of small leather boxes and straps containing portions from the Torah that observant Jewish men place on their heads and wrap around their arms during morning prayers.

This Friday, classes are over by noon and the boys are wolfing down a hot lunch of meatballs and noodle kugel, getting ready to head downtown with their tefillin bags. The boys will be taking the bus to Pioneer Courthouse Square, a renovated public plaza in the heart of Portland that is filled on a typical Friday afternoon with chess players, street musicians, lunching secretaries, punk skateboarders, and homeless teenagers.

It’s 1:15 p.m., and the day is slipping by. Motti, one of the counselors, stands up and claps his hands for attention. “OK, guys, let’s go! It’s very hot today, so drink plenty of water.” The boys grab their black hats and coats, which they don’t wear during class but always don when going out in public, and head for the bus stop. The bus pulls up, and the driver doesn’t blink when 22 Hasidic boys in full regalia troop past her and take their seats. The passengers, for their part, look too stunned to speak.

When the bus reaches Pioneer Courthouse Square, the Lubavitch boys pile out. They immediately break up into pairs and fan out in all directions. Some of the duos take up positions at the four corners of the square, strategically poised to approach anyone passing in either direction. Mendel is paired up with his buddy Ari Greenwald of Long Beach, California. The two boys head off to the north.

Mendel is in charge, arms swinging as he strides up the sidewalk. Once in a while, he and Ari confer sotto voce as to the possible Jewish status of an approaching man. “A Yid?” one asks, and the other either nods or shrugs. In general, they approach everyone. “Excuse me, are you Jewish?” “Sir, are you Jewish?” Within the first five minutes, they’ve asked more than two dozen men, without success. Then they come upon an unkempt, portly guy in his mid-thirties, wearing jeans, a T-shirt advertising a heavy-metal band, and a blue-and-white baseball cap that reads, “Bite Me.”

Jewish? Hmmm…maybe. Ari asks, halfheartedly, and strikes unexpected pay dirt. “Yeah,” the guy mumbles, his pale eyes trying to focus behind thick, round glasses.

“You are?” Ari asks, taken aback for a minute, but motioning Mendel with one hand as he keeps the guy talking. Mendel charges up and quickly assumes command. “Do you have a minute? Want to put on tefillin?” Mendel is all smiles now.

“I wish I had a minute,” the guy mumbles, but he doesn’t leave. He’s still standing there, shifting from foot to foot, waiting for the boys to talk him into it. “Come on, it’ll only take a minute, I promise,” Mendel urges, as Ari stands to one side, discreetly removing the leather tefillin from their velvet pouch. “All right,” the guy agrees, and quick as a wink, Mendel wraps the straps around the man’s plump left arm, once, twice, seven times, and does the crisscross across the left hand and an extra twist around the middle finger. As Mendel wraps, he says the appropriate prayer out loud, in Hebrew, word by word, slowly enough so that Mr. Bite Me can repeat each one after him. The man’s eyes are shut tightly, and he’s shaking slightly as he says the prayers. He needs prompting, but he knows how to pronounce the Hebrew. Clearly, he’s had some background. Maybe a day school graduate gone astray? Mendel and Ari exchange quick glances.

When it’s all over and the man opens his eyes again, he has to blink away a tear.

This is the kind of encounter a Chabad yeshiva boy dreams of. Mendel starts his follow-up patter: Where are you from? What are you doing for Shabbat? It turns out that the man is from out of town. He’s only been in Portland two days and has no plans for Friday night. Dinner at Chabad House? Sure, why not?

"Mr. Bite Me" was excerpted from The Rebbe's Army: Inside the World of Chabad-Lubavitch (Schocken Books, 2003), by California journalist Sue Fishkoff. Sue Fishkoff spent a year traveling to Chabad centers throughout the United States, from Anchorage to Salt Lake City to Boca Raton—and even attended a Chabad Seder in Bangkok, Thailand—to explore what motivates the Chabad shluchim and what draws ordinary, often non-observant, Jews to the movement.