There is a stained-glass window at the top of the wall behind the bima at the Montebello Jewish Center in Suffern.

It’s round and set deeply into the white of the wall; there is a foot or so of white surrounding it, providing it with depth and space, and room for the light from outside to play.

It’s new, but doesn’t look particularly modern, or particularly dated, for that matter. Its colors are delicate but not muted.

It’s lovely.

When you look at it from the back of sanctuary, you see the whole thing; when you get closer, the view changes.

Joshua Finkelstein, the synagogue’s new rabbi, says that he understands that people prefer to sit toward the back of the sanctuary so they can see it in full, but he prefers the view from up close, and hopes that the congregation will come closer to it as well. It is in the interplay of the light and the space, the colors and the light, the permanence of the window and the shifting of the light, that he can most easily find God, he says.

That’s another striking thing about Rabbi Finkelstein. Unlike many rabbis, he talks about God. He’s comfortable with his faith, and he wants to inspire others to explore their own, and in the context of the Conservative movement, into which he was born, in which he has generations-deep roots, with whose principles he resonates.

So who is he?

Joshua Finkelstein is a fourth-generation rabbi; he has major yichus in the Conservative movement and a 16-year history in northern Bergen County, right over the state line from Montebello.

To begin with his background, “my great-grandfather, Simon Finkelstein, came to this country in 1885, from Kovno, in Lithuania,” he said. “He studied at the Slabodka Yeshiva,” a prominent and important institution, “and he got his smicha from Yitzhak Elchanan Spektor,” the major figure who is the namesake of Yeshiva University’s rabbinical school, the Rabbi Isaac Elchanan Theological Seminary, perhaps better known as RIETS. “He didn’t get smicha from the place, he got it from the person,” Rabbi Finkelstein said.

“He served congregations in Baltimore, Cincinnati, and Syracuse, and then, for the last 30 years of his life, in Brownsville.”

Simon Finkelstein’s son, Louis, who grew up in Brooklyn, earned his undergraduate degree at CCNY and a doctorate at Columbia University. Those were fairly easy choices, but he had to decide where to get smicha — RIETS or the Jewish Theological Seminary. “My great-grandfather said to go to JTS,” Rabbi Finkelstein reported — “because JTS required a bachelor’s degree, and at the time YU did not. My great grandfather, the Orthodox rabbi, thought it was more academically rigorous. He respected that.”

Although the borders were more porous then,  JTS was then as it is today the flagship institution of the Conservative movement, as YU is of American modern Orthodoxy.

At first, Rabbi Louis Finkelstein “served at a congregation in the Bronx, off the Grand Concourse,” Rabbi Finkelstein said. “Kehillat Israel. It no longer exists, but it’s sort of funny; coincidentally, my wife’s grandfather used to daven there.”

Rabbi Joshua Finkelstein

Joshua Finkelstein’s grandfather was not just any Louis Finkelstein, though; he was the Rabbi Louis Finkelstein who became first an academic and then, for more than 30 years, JTS’s chancellor. “When he was leaving the pulpit to work full time at the seminary, his father said to him, ‘What is a rabbi without a pulpit?’” Rabbi Finkelstein reported.

Louis Finkelstein’s son, Ezra, perhaps unsurprisingly, also became a Conservative rabbi. His son, Joshua, was born in Brooklyn, grew up in Whitestone, Queens, where his father was the rabbi of the Whitestone Hebrew Center, and then, when Joshua was going into his junior year in high school, moved to Syosset, on Long Island, to become the rabbi of the Midway Jewish Center. Joshua had graduated from middle school at the Schechter in Queens and was in high school at Bronx Science — a challenging subway ride from Queens, although he did not make the commute alone, he reported — when he transferred to Syosset High School.

Joshua Finkelstein went to Columbia for his undergraduate degree. He decided not to go to the joint program between Columbia and JTS; “my father said that I should be sure what I wanted, because with our background, it would be too easy to fall into the rabbinate.” It should be a conscious choice, Ezra Finkelstein said.

It isn’t as if Joshua Finkelstein didn’t have Jewish connections. At Columbia, he studied with the talmudist Rabbi David Weiss Halivni. And he had his grandfather, who had retired by then but still lived in the neighborhood. “I spent every Shabbes at my grandfather’s table for 10 years, through college and rabbinical school,” except for the year he spent in Israel, Rabbi Finkelstein said.

He has many stories from that time of his life. Asked to find just one, he talked about how, on Shmini Atzeret, he would have the talmudist Rabbi Saul Lieberman “come over to celebrate his coming to America. Every Friday night my grandfather would ask me to lead the Birkat haMazon,” the grace after meals, “but he always had Elie Wiesel also on Shmini Atzeret, and he would ask Elie Wiesel to lead it that day.

“Elie Wiesel had a beautiful, soulful voice, and when he got to the part of  harachaman  about Shabbat, he would sing a wonderful niggun from Sighet,” the Hungarian town he came from. “It was a very soulful melody, and it would go on and on. He would sing it for a long time.” Rabbi Finkelstein sang it; it’s beautiful and haunting.

“So my grandfather said, ‘You know, I asked Elie Wiesel to sing it for you, because it is from Sighet, and I don’t want it to be forgotten. I know you will be a rabbi, and you will teach it.’

“And I felt the awesome weight of the Holocaust on my shoulders. I knew that I would be a rabbi, not a chazzan, but I would go on to teach it, but I always felt that I was failing.”

And then Rabbi Finkelstein heard someone else — a song leader in the Reform movement — sing that melody. He learned that it’s a standard among Reform Jews. Later, after Mr. Wiesel died, a CD of his talking and singing at the 92nd Street Y included the melody. It was no longer just Rabbi Finkelstein’s responsibility to pass it on, and that was a huge relief to him, but it remains his responsibility to continue to teach it, he said. In fact, he’s already talked about it at Montebello, at Selichot services.

It all goes back to the first time he heard it, at his grandfather’s Shabbat table.

While his father’s family taught him about Jewish life, his mother taught him about how to teach and treat and love children, and how to notice and encourage their individuality. “My mother, Elaine Samuels Finkelstein, was a teacher in the New York City public school system for many years. She taught special education in PS 48 in Hunts Point, in the Bronx, in a special state-funded preschool. She used to make sure that she’d bring us to visit the classroom at least once a year. She was very much into early intervention. She said that we could always make a difference, and that carried through to all of us and to our children.”

Rabbi Finkelstein’s father’s father’s family was the one most people know about, but his father’s mother’s family is notable as well. They were the Bentwiches; Herbert Bentwich, his great grandfather, was a very successful British barrister and a fervent Zionist who made aliyah to Palestine in 1929. “I am told that Herzl went to his house,” Rabbi Finkelstein said. He was the progenitor of a large, mainly Israeli family; as Ari Shavit told us in “My Promised Land,” he also was the journalist’s great-grandfather. (That, for the non-genealogists among us, makes Rabbi Finkelstein and Mr. Shavit fourth cousins.)

Rabbi Finkelstein and his wife, Elana Gershen, lived in Bergen County for 16 years; he was the rabbi of Congregation B’nai Israel in Fair Lawn and Temple Emanuel of North Jersey during that time; in fact, he was at Emanuel when it moved from Paterson to Franklin Lakes. Their three children, Sarah, now a doctoral student in biology at Columbia, Elie, a rabbinical student at Chovevei Torah, and Rebecca, a freshman at Wellesley, grew up there. The family moved to central Jersey for some time, but now Joshua and Elana are in Rockland, and it feels like home.

The Conservative movement also feels like home for Rabbi Finkelstein, both for its history and for its promise, he said. It’s not only family history but personal history as well; he practically grew up at Camp Ramah in the Berkshires, where his parents worked for many summers. His wife also was a lifelong Ramahnik — but she grew up in Princeton, so she went to Ramah in the Poconos. Her parents were deeply committed to their shul, and thinking about them led Rabbi Finkelstein to talk about how important lay leadership is. “I have a great appreciation for what they can do to make this world a better place,” he said.

As for the Conservative movement, “I know that people are wringing their hands about the future of Judaism, and about the movement, but I also see how other movements are emulating what we do,” he said. “Federations have Havdalah programs, and Chabad is opening Jewish centers.

“People are looking for Jewish connections, for meaningful Judaism, for a sense of the greater good, and for a sense of God in the world. If we can create a mindful, meaningful Judaism, where people are reflective about their lives, where they can create meaning in their lives, and if we can help shape that meaning, then this is a vehicle to help them transform their lives — and transform the world.

“And that brings me back to the Montebello Jewish Center,” he said. “I have come to a place where people are committed and loving. It is a wonderful place.

“I believe the focus of the rabbinate is to work with the community, to build the community, and to bring people closer to God,” he said.