On a billboard in Houston the other day a group of citizens put up their Christmas message for all the shoppers to see. "The perfect present," it said. "Send the hostages home for Christmas."

It was, in a way, the most appropriate kind of message for this season. For this last Christmas of the 1970's is surely one of the most subdued in years. After a decade of shocks to the nation politically and economically, a traveler around the country finds the mood somber, the tone quiet, the discourse serious.

In other times, the call for a "national unity day" would have brought a cynical curl to many lips. The name itself was reminiscent of those "Honor America" days that we saw so often during the decade. They were staged largely for political benefit and to quell dissent, to make a president look good in a time of trouble. But this time, the nation really does seem united.Those flags that were waved from bridges and buildings and passing cars accurately reflected the spirit of the country.

Iran, it appears, has achieved something beyond the reach of our political figures in years. In a supposedly self-indulgent -- if not selfish -- society, the taking of those hostages has forced a state of national selflessness and introspection.

Materialistic America, the cellophane civilization, awash in consumer goods, complacent, preoccupied with looking out for number one -- to hear many of the critics tell it -- is exhibiting other traits of character, and admirably so.

About this time every year, the usual sermon gets preached both from the pulpit and by the oracles of the press: "The Real Meaning of Christmas." While we listen and guiltily nod our agreement about our excesses of commercialism and acquisitiveness and our gluttonous appetites, we vigorously trample each other in our rush to get more.

But this year, if what one sees and hears reflects the nation at large, Americans really are thinking about some of the values implicit in Christmas. And there is a certain irony in this.

What has moved Americans goes beyond the prospect of violence or an insult to some amorphous national pride.

Violence has become so common a staple of American and world life that we are almost inured to it. Presidents and public leaders are murdered, airplanes are hijacked, hostages are slaughtered, and brutal acts of individual passion committed daily. We see it all, live and in color, and move on to the next act. National honor no longer has quite the ring of the more innocent past. We know too much about our own mistakes to be too jingoistic.

What stirs such emotions is the knowledge that these are innocent victims. Each of us can identify with them, with their fears and deprivations and humiliations, their sense of helplessness and isolation. We are all hostages with them. A people that can care so deeply about other individuals threatened, abused, and trapped in forces beyond their control can hardly be consumed with selfishness.

That this comes at Christmas provides fitting symbolism. Once again we are seeing a drama of suffering played out in the Middle East and cast by people who could step out of the pages of Biblical conflict. The human reactions of sympathy, anger and the desire for revenge collide with other emotions -- with love and affection and the spirit of good will -- that are supposed to be the hallmarks of the season. The threat of war in the most combustible and economically critical region of the world mocks the ancient tidings of peace on earth.

Yet if we are looking more into our own hearts these days, wishing to share the pain of the hostages and relieve their suffering, the experience cannot be all bad. It might even bring more awareness of the timeless Christmas message of hope.

For many, the words in the carol have special meaning this year: The hopes and fears Of all the years Are met in thee tonight.