LOS ANGELES – A federal courtroom here was briefly transformed into a seminar on Judaic tradition yesterday as an Orthodox couple pressed their claim that portions of their payments for their children’s tuition at a private Jewish day school should be tax deductible.

A rabbi testified and prayer books were handed around as a lawyer for the couple, Michael and Marla Sklar, attempted to convince a tax court judge that the schools are so religious that they are not comparable to most other private schools.

“The religious studies are in a class by themselves,” the lawyer, Jeffrey Zuckerman, said in his opening statement.

An attorney for the Internal Revenue Service, Louis Jack, warned that granting the Sklars’ deduction would open a Pandora’s box of litigation over private school fees.

“The court will be inviting every parent sending a child to private school to come into court and argue they did not get what they pay for,” Mr. Jack said. “Private school tuition payments whether for secular or religious education are not a charitable contribution.”

Mr. Jack also argued that requiring the IRS to figure out just how much education was religious and how much was secular would lead to a “dangerous entanglement of church and state.”

The Sklars sought the deduction after noticing that the IRS granted tax breaks to members of the Church of Scientology for their payments for religious training and a Scientology ritual known as auditing. In fact, Mr. Sklar testified yesterday that the IRS granted him some of the deductions he claimed under the mistaken impression that he is a member of Scientology, a religious group founded in the early 1950s by a science fiction writer, L. Ron Hubbard.

Mr. Sklar, who is a certified public accountant, said yesterday that he called IRS officials to make clear that he is not a Scientologist. He said he told them, “Now that I know you do the same thing for Scientologists, please do the same thing for me.”

One of Mr. Zuckerman’s tasks at the trial will be to show that the Scientology practices and the Jewish religious studies are similar enough to require that the Sklars be granted the same deduction. “Under the First Amendment to the United States Constitution, IRS may not discriminate on the basis of religion between two taxpayers,” Mr. Zuckerman said.

Judge John Colvin has made Mr. Zuckerman’s task more difficult by rejecting his requests to subpoena the Church of Scientology and its president, Heber Jentzsch. The judge has also rejected the Sklars’ effort to force the IRS to produce a copy of a 1993 agreement in which it promised to allow Scientology followers to deduct certain payments to the church. The judge has offered no explanation for his decisions, and yesterday he declined to reconsider them.

In 1997, a leaked copy of the agreement between the government and Scientology was obtained by the Wall Street Journal and posted on its Web site. When Mr. Zuckerman sought yesterday to introduce the newspaper’s version of the agreement, the IRS lawyer objected.

“There is no way to know” if it’s authentic, Mr. Jack said.

Mr. Zuckerman was clearly frustrated with that response. “There is someone who knows,” he told reporters later, pointing out that the document was signed by IRS representatives. “To me, it’s Kafkaesque.”

Mr. Zuckerman stressed that his clients are not challenging the government’s agreement with Scientology, but simply seeking equal treatment.

“We think they’re right to be allowing the Church of Scientology to take that deduction. We fully support that decision,” he said.

In an earlier challenge brought by the Sklars, the 9th Circuit Court of Appeals suggested that the deduction for the Scientologists was constitutionally dubious but that the courts should not expand the deduction to cover religious education for taxpayers of all faiths. Instead, the court said, any preferential treatment for Scientologists should be ended.

In the 2002 decision, the appeals court stopped short of striking down the IRS policy. It is unclear whether that outcome is a possibility in the new proceeding, chiefly because the Church of Scientology is not a party to the case and has not been formally called on to defend its agreement with the IRS.

At the trial, which began yesterday and is expected to last for several weeks, Mr. Zuckerman sought to show that the religious education received at an Orthodox Jewish day school is far more than an intellectual pursuit.

Speaking of the Jewish holy writings known as the Torah, Mr. Sklar said, “It is a living breathing text which actually has an effect on body and soul…. That’s what recharges us and renews our link with God.”

The court also heard from a rabbi who heads one of the schools attended by some of the Sklars’ six children. Rabbi Yaakov Krause of the Torath Emeth school said that while students there are taught traditional academic subjects in the afternoon, religious studies occupy the morning hours and are clearly favored.

“The fact that we have these Judaic studies in the morning goes a long way to setting the priorities straight in the minds of the students,” he said. “I don’t know any parent that would send their students to our school for the general studies program.”

Rabbi Krause said students spend their mornings studying subjects such as prophets, Jewish law, and the Talmud. Math and science sometimes get short shrift, he said, adding, “We didn’t have a science lab. We had a cart.”

Asked what he would do if he found out that all the graduates of his school had gone to Harvard, rather than a Jewish seminary, the rabbi said, “I would look for early retirement.”

The IRS lawyer, Mr. Jack, tried to demonstrate that some of the school’s religious agenda spills over into the ostensibly secular classes. Under questioning, Rabbi Krause acknowledged that the school doesn’t teach evolution in its science classes. “Certain textbooks are screened for appropriate content.”

To accommodate the Sklars and Mr. Zuckerman, who is also Orthodox, the court took a 15-minute prayer break yesterday afternoon.

In addition, Mr. Sklar and Rabbi Krause affirmed that their testimony was true rather than taking the traditional oath. Many Orthodox Jews believe they should not take oaths before God as part of a secular event, such as a court trial.