It was a melting-pot party.

The hot and crowded room last night at the Shoreham Hotel was filled with Washingtonians from way back. Although the National Conference of Christians and Jews was the name of the affair, the cauldron brimmed with an even wider mixture of people.

The benefit dinner, with 700 tickets sold at $160 each, honored Katharine Graham, chairman of the board of The Washington Post Co., and R. Robert Linowes, former president of the Greater Washington Board of Trade. They were chosen this year's local recipients of the NCCJ National Brotherhood Citation, given in recognition of their contributions to the improvement of community relations.

"As I look around this room," Graham said in accepting the award, "I cannot help but feel how fortunate so many of us are to have had our lives and careers take place, by chance, in the District of Columbia. This city--this metropolitan area--has been good to us."

Her comments reflected the community theme of the evening, matched with a guest list that included Maryland Gov. Harry Hughes, former D.C. mayor Walter Washington, Effi Barry, Del. Walter E. Fauntroy and the Rev. Leo J. Coady, pastor of the Holy Redeemer Church.

"If we have a task in the days ahead," Linowes said, "it is to spread the word and to recruit--coworkers, friends, neighbors, relatives, whomever . . . all are fair candidates for enlistment. An army of missionaries? No. But a force for change, yes."