Standing obediently beneath a banner proclaiming, ''Faith is the key in '83, '' the Bangor Christian School choir is practicing for its spring tour. On cue, the young, a cappela voices fill the cathedral-ceilinged auditorium: ''How can I say thank you for what you have done for me? The voices of a million angels could not express my gratitude for what I am.''
Such sentiments aren't reserved for choral exercises here at Bangor Christian , where the first book studied every morning is the Bible. Like the 60 or so other private fundamentalist schools in the state of Maine, Bangor Christian requires its curriculum to fully incorporate born-again Christian teachings. But now the freedom of that school, and others like it, to exercise this prerogative is being called into question.
Faced with the periodic certification of teachers, as required by state law, the Bangor Christian school is suing the state for infringement of federal civil rights law. Twenty other fundamentalist schools in Maine are joining in the suit.
''We cannot tolerate the state having final authority in selecting our teachers and curriculum,'' says the Rev. Herman Frankland, executive director of the Maine Association of Christian Schools and pastor for the 2,000-member Bangor Baptist church. ''We are as opposed to the state approving our schoolteachers as we are to its approval of our Sunday-school teachers.''
Rufus Brown, the Maine deputy attorney general involved in the case, sees things in a quite different light. ''These schools say we can't have control over their teachers. But how should the state protect the public interest? The (fundamentalists) simply want to put whomever they choose in the classroom. And we believe that there are teachers out there who are simply unqualified.''
It is the first case of its kind to go as high as a federal court. And its outcome, anticipated sometime in June, could establish a national precedent.
At issue is the need for a balance between religious freedom and states' obligations to ensure sound educational standards for all its citizens. Traditionally, mainstream parochial schools have not contested state education requirements for private schools. But such requirements are coming under fire from conservative Christian schools.
Since the mid-1970s, half a dozen cases have been brought to court by private Protestant schools, whose ranks are burgeoning. The schools contend that state licensing of private schools, certification of teachers, and curriculum guidelines are, in their cases, violations of church and state separation as guaranteed in the US Constitution's First Amendment.
The fundamentalists have lost the majority of those cases, most notably a 1981 Nebraska case where a principal was jailed for violating a court order to abide by state regulations. But a recent Michigan decision indicates that the tide may be turning in the schools' favor. In January, a Michigan judge struck down state laws requiring certification of private-school teachers and curriculums. That decision, now being appealed by the state, was later amended to apply to only the two Christian schools named in the suit.
William Ball, attorney for the schools in both the Michigan and Maine cases, says the First Amendment is at issue. ''The constitutional questions we want addressed include the rights of pastors and parents to enjoy the free exercise of religion, the parental right to secure the kind of education they desire for their child.'' State education requirements for private schools, maintains Mr. Ball, constitute a clear violation of church and state separation.
While many Christian schools are considered ''traditional schools,'' meaning they operate with approved textbooks, separate classrooms, and teachers for each grade level, an increasing number of fundamentalist schools are relying on a workbook curriculum. This type of educational system is causing alarm among many educators. A for-profit organization, Accelerated Christian Education (ACE) of Lewisville, Texas, publishes and sells its ''total church education package'' to any fundamentalist church interested in setting up a school. Supporters of the program say ACE would like a school in every fundamentalist church. ACE officials list more than 4,000 schools in the US using their materials. Attendance at these schools, they say, is ''in the millions.''
Indeed, all types of Christian schools have proliferated during the past decade. Concerned about everything from drugs to discipline and citing a decline in instruction that promotes Judeo-Christian values, increasing numbers of parents have pulled their children out of public schools and put them into private Christian academies. From only a handful 10 years ago, fundamentalist Protestant schools are now estimated to number more than 5,000.
While most mainstream parochial schools - Catholic, Lutheran, and Jewish private schools - have long abided by state education requirements, the fundamentalist Christian schools are choosing to fight them. Why?
''State agencies make laws for private schools without realizing that religious schools might object,'' says Dr. Paul Kienel, executive director of the California-based Association of Christian Schools International. ''Other parochial schools aren't as sensitive to those rules. They're also quicker to accept state and federal aid. But fundamentalists schools don't (accept public money). They consider themselves part of the church and you don't make state rules for a church.''
The Rev. Mr. Frankland agrees. ''For us, this church and this school are one and the same. The school is the teaching arm of the church. So the bottom line is this: Who controls the church and her ministries? Is God the overseer or is it the state? We have said the Lord Jesus Christ rules this church and not the state.''
Bangor Christian School, like most other fundamentalist schools, requires that all its teachers be born-again Christians. ''Our first criterion for teachers is do they feel called into a ministry of education,'' continues Mr. Frankland. ''Needless to say we try for academic excellence, but that is not our first criterion. So we start on a totally different premise than the public schools.''
Patty McLeod, a first-grade teacher at Bangor Christian for five years, is one of the many teachers in the school up for certification renewal this summer. She explains her refusal to seek state certification renewal: ''A Sunday-school teacher wouldn't need certification. Besides, I don't think certification makes me a better teacher.''
Others disagree. ''We believe every child in the country deserves to have a fully certified teacher,'' says Bernard McKenna, a teacher education specialist with the National Education Association. ''Certification ensures that a teacher will be qualified to teach. Its absolutely essential. We certify other professionals. Why should a person belonging to a particular religion be exempt from that?''
Bangor Baptist church members who have their children enrolled in the school - approximately 95 percent of the congregation, according to church officials - are just as adamant about the school's stance.Mrs. Glenda Garland explains that her husband has had to take an out-of-state job in order to cover the $300 -a-month school fees for their three children. But it's worth it, she says. ''We want our children to learn sex education at home. We want them to learn right from wrong. In public school they were getting a lot of different moral viewpoints than what we wanted to give them.''