In the vast magnificence of the Pension Building, President Reagan counseled his audience: "Take comfort and joy in our children, and with them pray for 'on earth peace, good will toward men.' "

Taking a break yesterday from his weekend campaign to rescue tax reform legislation from a congressional death blow, the president spoke to a more receptive crowd, the audience for NBC's annual "Celebration of Christmas in Washington," broadcast later in the evening.

The president and his wife Nancy -- who swung her foot ever so slightly in time to the music -- watched the show from the front row. "NBC Nightly News" anchor Tom Brokaw was host of the hourlong show, which starred Pat Boone, Natalie Cole and Christian rock star Amy Grant, as well as violinist and Soviet defector Viktoria Mullova and 13-year-old gospel singer Kenneth Mack Jr.

American Film Institute founder George Stevens Jr., who conceived the show, now in its fourth year, joked to the live audience about the merger of General Electric Co. and RCA, the parent company of NBC:

"We can call the show 'The GE Christmas Theater.' I have an idea for a host, but I guess we'll have to wait three years." Reagan, who was host of "General Electric Theater" in the '50s, grinned. Stevens also noted that GE was the manufacturer of the more than 2,000 Christmas lights that graced the museum's Doric columns.

NBC Chairman Grant Tinker said that no matter what people say about the rivalry between NBC's news and entertainment divisions, Tom Brokaw's presence on the show was "proof positive that the Christmas spirit is alive." Brokaw did mini-interviews with the show's entertainers, including Mullova and Mack. Later, Mack said he was put up to saying he wasn't nervous when he met the president and sang for the pope but that he would be to meet Michael Jackson. "I'd like to meet him but I wouldn't be nervous," Mack clarified.

After joining in singing "Hark, the Herald Angels Sing" with the Shiloh Baptist Church Choir and the U.S. Naval Academy Glee Club, the Reagans left. This week Nancy Reagan goes to Children's Hospital with toys donated last night, including two teddy bears (one in a dress, one in a suit) the Reagans brought themselves. (Not that the children who attended last night -- families of Cabinet members and executives from NBC and the show's sponsoring companies -- went home empty-handed. They each got white teddies as favors.) The show's sponsors also are giving the medical center a mobile intensive-care unit for newborns and will underwrite the cost of a kidney dialysis machine.

After the performance, the crowd spread over the west court of the 316-foot-long building to enjoy a Dickens Christmas feast from draped and beribboned tables.

Bates Lowry, director of the National Building Museum, proprietor of the Pension Building, said the evening was a far cry from the first "Christmas in Washington" special four years ago. That year, Lowry said, a staffer came running in and said, "We don't have any chairs and George Stevens has to sit on a wastebasket."

Stevens was in good spirits about the Christmas tradition he started. "I like traditions. When my children were young," he said, "I always wanted something exciting for them to do at Christmas time." Stevens told Mack, who just celebrated his birthday, that "Mrs. Reagan told me to tell you how wonderful she thinks you are." Amy Grant, receiving compliments on her multiple costumes for the show, said, "I live in jeans on our farm outside Nashville, so when I got a chance to dress up, I brought everything I had."

Tom Brokaw, who read Henry Wadsworth Longfellow's "I Heard the Bells on Christmas Day," said, "That's the first time I've read a poem out loud since I was 7 years old."

The evening was best summed up by the president, who when putting his teddy bear under the tree, was asked questions about the tax bill. "All I've got to say is 'Merry Christmas,' " he said, and waved.