A few weeks ago, the sheriff of Cass County, Neb., court order in hand, padlocked a Baptist church to prevent its fundamentalist school from conducting classes.

Last December, the sheriff of Pawnee County, Neb., also armed with a court order, seized and auctioned off a buggy belonging to an Amish family who refused to pay fines imposed for breaking the state's education laws.

And on Oct. 28, a fundamentalist preacher acknowledged before a legislative committee that he and his allies in the state, generally fervent champions of "law and order," were indeed engaged in civil disobedience.

"Yes," said the Rev. Carl Godwin, "we are breaking the law. But there comes a time when we feel man's law has gone too far."

The Nebraska law in question is responsible for some of the strangest scenes in the recent annals of church-state relations. It requires state approval of all teachers, and of all schools that educate children.

It is a commonplace law, though many states exempt religious schools and others choose not to enforce it against them. But it is increasingly challenged by the growing number of small fundamentalist elementary and secondary schools, attended by the children of parents who have opted out of the public education system.

They call their schools "Monday schools." They say that their Monday schools are no different than their Sunday schools, that they are an integral part of their church ministry.

Since the state may not license or approve their religious ministries, these fundamentalists, U.S. Constitution in one hand, Bible in the other, say the state may not interfere with their schools.

Godwin, a spokesman for many of these schools in Nebraska, says that about 20 of them are violating the law. Others are battling officials in Iowa, North Dakota, Michigan and six other states that do not exempt religious institutions from their laws. The pastor of a church-operated school in Fairfield, Iowa, was fined by a judge for defying a court order closing his school.

Godwin said that the smaller of these schools (some in rural western Nebraska enrol fewer than half a dozen students) will not survive if forced to comply, since they cannot afford certified teachers.

Teacher certification and curriculum approval have been features of school regulation in this country for years, though scholars testifying before a legislative committee in Lincoln Oct. 28 acknowledged that the effectiveness of certification in particular has never been proven and the religious critics argue that they exist simply to protect jobs. "Mainline" church-affiliated schools, such as Catholic schools, have chosen to comply.

While the courts have allowed some exemptions from compulsory education laws for religious minorities, such as the Amish, they have generally regarded these requirements as minimal intrusions on religious practice, justified by governments' need to maintain educational standards.

So the courts in Nebraska rejected the "Monday school, Sunday school" argument. It was after the Supreme Court of Nebraska's rejection of it last January, followed in September by the U.S. Supreme Court's refusal to hear the case, that the latest episode in the struggle unfolded: the padlocking of the Faith Christian Church in Louisville, Neb.

Located 10 miles off Interstate 80 between Omaha and Lincoln, Louisville looks more like Appalachia than the Great Plains. Its small houses, grayed and dusty from the towering cement plant that guards the entrance to the town, sit uncertainly on successive levels of eroding hills, not solidly on flat and fertile fields.

In 1976, Pastor Everett Sileven, "born-again" at the age of 9, opened his independent Baptist Church and school there. The school's enrollment has fluctuated between 30 and 19--K through 12. Its curriculum is provided by Accelerated Christian Education Inc., a Texas-based organization that services such schools throughout the country. It is a different kind of school.

It is, first, a one-room schoolhouse, occupying the ground floor of the church. The students work at long tables, hinged to the walls. No one lectures to them or stands before them and talks. Instead, they spend their days, all ages together, studying from ACE workbooks. The workbooks leave no doubt about their mission.

Consider, for example, an elementary science text. "This world belongs to God," it says, for openers. "God made this world in six days . . . . Thank You, God, for this world You made."

The opposite page features an exercise in which the students are asked to draw a line between the words and the picture. "Day one" is supposed to be connected with pictures of day and night, light and dark, "day two" to the sky, clouds and air, and so on.

The social studies text for small children focuses on the life of David Brainerd, an 18th century missionary who, it says, "was willing to face many hardships to reach the Indians with the Gospel."

All of the texts include standard grade school fare as well, but even the math books are laced with biblical sayings and cartoon strips showing proper Christian behavior.

A student advances to another stage in each subject by passing a test, not by aging another year.

The ACE curriculum has been approved by Nebraska education officials for those schools which, unlike Sileven's, have submitted it. The individual attention provided by the schools and the subject mastery required for promotion have been praised by education experts. And the children at Faith Christian School, according to the pastor, have scored substantially higher than children in the surrounding public schools on standardized achievement tests.

The real controversy centers around the teachers, called "supervisors" and "monitors." Children needing help summon them by placing a flag in a slot on the work table.

Making sure they are capable of helping is what the controversy is all about.

To be certified as a teacher in Nebraska, as elsewhere, an applicant must have a college degree, a certain number of courses in the subject to be taught and a certain number of courses in methods of teaching.

To teach at Faith Christian School, according to Sileven, applicants must be born again, belong to the Faith Christian Church, lead a "separate life--no drinking, no cussing," be interested and capable of relating to children and capable of disciplining them, and attend at least 40 hours of ACE training.

Sileven has refused to have anything to do with certification. In addition to citing the Monday school, Sunday school argument, which he says cloaks his school with First Amendment religious freedoms, Sileven sees certification and state approval as a form of "contamination."

"The public schools and the state of Nebraska are pushing secular humanism," he said, invoking the current phrase used by fundamentalists to describe the root of most of the nation's troubles. "How can they interfere here without contamininating my program?"

The courts, too, he says, "are now staffed by judges who are secular humanists who believe that all of life's issues are to be separate from religion . . . . That," he says, "is the old socialist and communist idea."

It was the courts, finally, that brought Sileven to national attention. After five years of efforts to obtain voluntary compliance and litigation, and the continued refusal of Sileven to obey the law as interpreted by Nebraska's courts, a county judge ordered the school closed down. The county sheriff implemented the order by padlocking the building on Sept. 13, unlocking it only for purposes of worship.

For a brief period Sileven's forces maintained a vigil inside the church to keep it open for the school. Ultimately, however, he took his supervisor, his monitor and his students into exile, conducting their classes at other Christian schools in Iowa and Omaha. The padlock was removed and the dispute defused, at least temporarily, while the legislative committee considers whether to change Nebraska law.

(A sub-controversy erupted Oct. 24 when Moral Majority leader Jerry Falwell appeared for a rally at the church to be shown on his television program. Since the lock was by then removed, church officials installed their own for visual effect, Sileven later acknowledged.)

All of this has been intensely embarrassing to state and local officials attempting to enforce the law, says Joe Stehlik, the Pawnee County attorney who had to move against the Amish.

In the case of Pawnee County, officials invoked criminal laws against the families attending an illegal school. When one of the families refused to pay court-ordered fines totaling $400, the father's buggy was seized and auctioned.

"We've gotten an extreme amount of ill will," said Stehlik. "But the papers haven't reported that we waited two years" for compliance by the Amish family.

"We're chastised for being overzealous. But we aren't in a position to treat these people any differently than anyone else who breaks the law."