President Carter, speaking last night at the lighting of the National Christmas Tree, expressed the hope that the fervor with which nations and peoples once sought victory in war "now can be devoted to our search for peace."

War no longer is the "brave sound of parades, drums and trumpets, the president told an estimated 10,000 persons gathered in the cold twilight on the Ellipse. "We've seen it as it is," he said, describing carnage, destruction and the threat of nuclear holocaust.

In his talk at the ceremonies, which opened the annual Christmas Pagent of Peace, the president also referred to Israel and Egypt as on the "threshhold of agreement" that could bring peace to the Middle East. He gave no details of any current negotiations.

For the ceremony, Washington's own special blend of Christmas and charisma, the Ellipse became a vast outdoor arena in which a chilled but uncomplaining audience enjoyed and endured an hour of music, songs and speeches.

Bundled in hats, mittens, boots and parkas, looking like a living catalogue of cold weather wear, they sat on 6,400 folding chairs or stood behind the seats as pale ashes from a flaming Yule log streamed like snowflakes over their heads.

Clergymen offered prayers. The pale blue of twilight deepened to the ink black of a clear, starry night as a full moon slowly rose in the east behind the bare branches of the elms ringing the Ellipse.

At about 5:30 p.m a phalanx of stern-eyed Secret Service agents took positions around the floodlit stage. Shortly afterward, a bareheaded man in a black raincoat strode without introduction from the wings toward the front of the stage.

It was the president. Within a few seconds, the U.S. Army Band, in its scarlet military caps, stuck up first Ruffles and Flourishes, then Hail to the Chief.

When his turn to speak came, the president stepped to the lectern, opened the top buttons of his coat and took out some papers.

"Merry Christmas," he began.

The response, from an audience long silent and perhaps somewhat uncertain of propriety, seemed little more than a murmur.

"C'mon," the president said, smiling. "Merry Christmas" the crowd replied.

The president spoke of peace, and of unity, the theme of this year's pageant, and of the dedication of the United States to acheiving these goals.

Then he took his daughter Army by the hand and with Mrs. Carter walked from the stage toward the tree.

For a moment they seemed to have vanished in the crowd. Then, suddenly, the tree, a living 30-foot Colorado spruce, was ablaze in red and gold light.

From the audience came a long, admiring "ahhhhhhhh."