Greice Coelho, who took Mr. Paszkiewicz’s class and is a member of his youth group, said in a letter to The Observer, the local weekly newspaper, that Matthew was “ignoring the First Amendment to the United States Constitution, which gives every citizen the freedom of religion.” Some anonymous posters on the town’s electronic bulletin board, Kearnyontheweb.com, called for Matthew’s suspension.

Image Matthew LaClair taped his history teacher talking about God in class. Credit... Jeremy Sparig for The New York Times

On the sidewalks outside the high school, which has 1,750 students, many agreed with 15-year-old Kyle Durkin, who said, “I’m on the teacher’s side all the way.”

While science teachers, particularly in the Bible Belt, have been known to refuse to teach evolution, the controversy here, 10 miles west of Manhattan, hinges on assertions Mr. Paszkiewicz made in class, including how a specific Muslim girl would go to hell.

“This is extremely rare for a teacher to get this blatantly evangelical,” said the Rev. Barry W. Lynn, executive director of Americans United for Separation of Church and State, a nonprofit educational association. “He’s really out there proselytizing, trying to convert students to his faith, and I think that that’s more than just saying I have some academic freedom right to talk about the Bible’s view of creation as well as evolution.”

Even some legal organizations that often champion the expression of religious beliefs are hesitant to support Mr. Paszkiewicz.

“It’s proselytizing, and the courts have been pretty clear you can’t do that,” said John W. Whitehead, president of the Rutherford Institute, a group that provides legal services in religious freedom cases. “You can’t step across the line and proselytize, and that’s what he’s done here.”

The class started on Sept. 11, and Matthew quickly grew concerned. “The first couple of days I had him, he had already begun discussing his religious point of view,” Matthew, a thin, articulate 16-year-old with braces and a passion for politics and the theater, recalled in an interview. “It wasn’t even just his point of view, it went beyond that to say this is the right way, this is the only way. The way he said it, I wasn’t sure how far he was going to go.”