His doctors had told him to remain very active, Hubert Humphrey was saying, "But I didn't need that recommendation." He had run, and lost, and he was philosophic about it. He would continue to be active "as long as I have the breath of life."

For Hubert Humphrey, yesterday was a time for reflection, for receiving tributes from his political peers and the public, not for dwelling on defeat. He had entered one last race - for majority leader of the Senate - but it was not to be.

He knew it when he got up in the morning. At 8 o'clock he called his opponent, Robert Byrd of West Virginia, and said he was withdrawing from the contest. He didn't want to leave any wounds or bitterness, he told Byrd. Humphrey wanted a harmonious relationship.

A show of harmony is something the Democrats can afford these days. They control both houses of Congress and are about to occupy the White House. And a display of respect is something they owe Humphrey, who has been in the forefront of their battles for a generation. They offered both yesterday as the 95th Congress convened.

They had met for nearly three hours behind closed doors off an ornate lobby in the Capitol. When the caucus ended, Byrd went out of his way to salute Humphrey.

He had appointed a committee to study a special post for Humphrey. Not that Humphrey needed a new office or a new assignment, Byrd quickly added: "he is, has been and always will be a national leader." Later, in the ritual surroundings of the opening of the Senate, members on both sides of the party aisle stood and gave Humphrey an ovation as he again assumed his seat. They were joined in their applause by the spectators in the galleries.

What was being played out in both the Democratic caucus and Senate chamber was more than sentimental affection for a favorite politician who has been seriously ill. Power was being passed. That reality lay behind all the ceremonial trappings of the day.

Washington is a town that thrives on ceremony, continuity - and change. All were present yesterday. Outside the Capitol - and the White House - workmen were constructing the inaugural platforms for the ceremonies two weeks away. But inside the Capitol itself the past still seemed dominant.

As the Democratic senators filed into their caucus room they passed they portraits of previous leaders. Daniel Webster, dour baggy-eyed orator and brandy drinker, peered toward the patrician Charles Sumner, equally unsmiling, but looking well fed. Sumner, in turn, gazed at a saturnine John C. Calhoun, a study in black, and a prim Henry Clay, hands folded neatly in his lap.

Humphrey strode into view, his step jaunty, smiling widely, but looking notably thinner and paler. For the last few days he hadn't been feeling well, he said later. A touch of flu. When the caucus was over, he said he thought he would rest a bit in the Senate gym before hosting a reception later in the afternoon. But he didn't; he headed straight for the Senate chamber.

On the floor it was Humphrey who attracted the most attention, Humphrey who was greeted most warmly by old and new. He chatted at the back of the chamber with Walter F. (Fritz) Mondale, a Humphrey protege from Minnesota who is about to assume Humphrey's old job and preside over the Senate as Vice President. He greeted many others who, like himself, had sought the presidency unsuccessfully over the years - Muskie of Maine, Jackson of Washington, Church of Idaho among them.

He bounced in and out of his seat, then marched alongside the newest senator from Minnesota, Wendell Anderson, as they signed their names in the official roster.

Looking down on that scene you could see men who had served in the Senate when it was the center of national political power, the springboard for the presidency, the place that provided the forum for John and Robert Kennedy, Lyndon Johnson and Richard Nixon. That, too, was changing now. Presidential power was shifting to a once obscure Southern governor and a group of Georgians who never worked in Washington.

What their relationship would be with the new Senate leadership was unclear. That would form the next political act. But that wasn't the question yesterday, for yesterday the spotlight was fixed clearly on Hubert Humphrey.

After taking his bow in the Senate, Humphrey talked about his unsuccessful effort at becoming the Senate's leader, about his health and the aftermath of his cancer oparation, and about his own future.

He lost for several good reasons, he said. He had started too late, tradition was against him in that the party whip normally becomes the leader, and there was concern about his health.

"Senators are a very unusual breed," he said. "When they give their word they keep it." His colleagues had given their word to Byrd last summer. That was that.

As for himself, he was content. "Once you've gone through a little thing like I've gone through you're just glad you're here." And then there was his sense of the moment: "I like them," he said, referring to his colleagues; "They seem to like me. I've had a good life. I intend to have more of it."

Someone asked him about Jimmy Carter and the promise of change. In replying, Hubert Humphrey spoke as much about his own career as that of the next President's.

"The dream," he said, "sometimes is larger than the reality."