WITH the world groping for solutions to the nuclear threat and diplomats focusing on imminent arms talks between the Americans and the Soviets, the theme of peace is in the Christmas thoughts of many pastors and theologians across the nation.
But it is not simply a state of non-war or security from humanity's problems which they contemplate.
''Peace has to be coupled with justice,'' says the Rev. Dr. Bruce Birch of the Wesley Theological Seminary. ''Peacemaking is an important task, not in the narrow sense of political concerns or foreign policy, but in the broader sense of the things that make for peace and lay the foundation for it. I try to get people to look at what might contribute to justice in their communities, to think about it at the Biblical level of 'shalom,' which is not the absence of war but a wholeness and harmony of their lives.''
The United Methodist Church, says Dr. Birch, is launching a four-year program about peace with justice. Echoing the recent action by Roman Catholic bishops, it is preparing a major statement on nuclear war, and that is much on the minds of Methodists these days.
The Rev. William Sloan Coffin, the lively, thought-provoking pastor of Riverside Church in New York, is focusing this season on the theme of love and joy, but not a sentimentalized love or a ''chirping optimism'' born of ignoring the dark sides of society. He wants Christians to ''look at the darkness'' so that they might see the light.
''We live in a great deal of darkness in the US,'' he explains. ''I do not see how Americans can feel proud when 15 percent of the people are poor or when 15 percent of our blacks can't find work. That represents a moral deficit in this country. I'm angry that the churches allow charity to take the place of justice.''
''The danger of Christmas is not commercialization but sentimentalization, not seeing the darkness,'' the former Yale University chaplain says. ''If you lower your quotient of anger at oppression, you lower your level of love for the oppressed. At the moment the churches that are significant are those that are taking on the public sector in challenging and provocative ways.''
Another clergyman, in his yule message, picks up on ''star wars,'' the burning issue of a potential Soviet-American clash in space. The Rev. Dr. Everett Goodwin of the First Baptist Church in Washington speaks of a different kind of ''star wars'' that relates to the significance of Christmas.
King Herod of the Bible perceived the importance of a star, he points out. So did the wise men and the shepherds looking after their flocks on the Judean hills. Yet they interpreted the bright event differently.
''Herod saw threat and change and a message from God different from the one he would like,'' says the Baptist minister. ''But others saw alteration of injustice and a new hope. So I call it the war between the stars.''
''All of us see two stars,'' he comments. ''Are we going to follow the star of Herod and try to tame it? Or will we be open to God's message of care for one another? It's not so simple as just being cuddled by the Christmas story and then it's over. It's evidence of something powerful happening among us, and its power is often thwarted if we cannot see it.''
Some churchmen are struck this year by the ''combativeness'' among Christians themselves, as reflected in arguments over the display of nativity scenes, or creches, in their communities.
The Supreme Court now has nine cases pending on church-state issues.
''I deplore the disturbance over the creche cases, and it is out of character with the Prince of Peace,'' says the Rev. Robert Maddox, head of Americans United for Separation of Church and State (AU) and an ordained Baptist minister. ''The whole combative attitude of church people and lack of effort at reconciliation is deplorable. It gets to be a matter of 'if I can prevail I will ,' regardless of what that does to the spirit of Christmas.''
AU's position is that the government should not pay for any displays of Nativity scenes; that a legitimate private group has the right to use government property to put up a creche; but that it is preferable to keep creches on private property to avoid community divisiveness and the ''reducing of Nativity scenes to the level of Rudolph the Reindeer.''
''If we're going to keep the Christ in Christmas, we don't have to have Nativity scenes on the Ellipse'' in Washington, Dr. Maddox says.
The controversies stem from the growing pluralism in America. The Rev. Dr. Martin Marty, associate editor of the Christian Century, says that today there are 2.5 million Muslims in the US, as large a group as such mainline Christian denominations as the Episcopalians or Presbyterians. In solidly Republican and conservative Du Page County of Illinois, he says, there are 40 kinds of non-Christian religious services on a weekend.
On the other hand, the non-Western religious cults have crested, says Dr. Marty, and families have far less concern that their children will join a cult.
Touching on the state of the Christian churches, the church historian notes that the mainline Protestant denominations have reversed their slide; the Roman Catholic Church continues its modest growth; and black churches are thriving.
Marty says the fundamentalists, who were in the shadows for 50 years, have grown not in numbers but in ''morale and visibility.'' They have become more assertive in recent years, and while it was the Northern, urban and suburban white churches that once had access to power, it is now Southern evangelical groups that get into the White House.
''So power has shifted now,'' he says, although the fundamentalists have not shaken the old culture.
In terms of its hold on the nation's culture, says Marty, Christianity is about where it was a few years ago. But it has not done much with the ''Yuppie'' culture - a group that lives in high-rise apartments, has a high intellectual level, and leads a highly pressured life. ''These are the least reached,'' he says.
An interesting development, the clergyman adds, is that sometime in the 1980s there will be more Christians celebrating Christmas in midsummer than in midwinter: The Christian majority is shifting to south of the equator, with the largest growth being registered in Africa, because of population increases and conversions.
From his pulpit in famous Crystal Cathedral in Garden Grove, Calif., the Rev. Dr. Robert Schuller is scheduled to deliver seven Christmas services this evening, stressing the ''unbelievable possibilities'' of development for the individual if God comes into his or her life. The greatest problem in the world, he says, citing microbiologist Rene Du Bois, is not nuclear war or poverty or famine but the ''loss of pride in being human beings.''
''The ultimate human value is self-esteem, and the absence of it is the cause of almost all the problems in the world and in an individual's personal life,'' says Dr. Schuller. ''The question is: How do we develop an authentic sense of self-worth when there are so many forces in society that cause us to underrate ourselves?''
''But no person is too small to contain God's love,'' says Schuller, minister of the Reform Church in America. ''Every life can have infinite development and tremendous self-worth. We better not forget who we are - human beings created in the image of God, who can unleash enormous possibilities in us.''
At the Calvary Baptist Church in Washington, which Warren Harding and Charles Evans Hughes used to attend, the Rev. Dr. George Hill is also highlighting the Biblical theme of peace. He has devoted Sunday sermons to peace for the individual, the family, neighbors, and the world.
''The Christian conscience has been sensitized in recent years to the potential threat of world destruction, and Christians are as concerned as any group of people can be,'' he remarks. ''There is so much mindlessness in the world in terms of preparation for war that we think this message is appropriate.''