Black leader Nelson Mandela, recalling his tough prison life and preparing to celebrate his first Christmas in almost 30 years as a free man, called Monday on the black majority to vow never to spend "another Christmas in chains."

"The message we wish to convey to you all is one of hope. . . . We have a right to be free, and we shall be free," the African National Congress deputy president said in a Christmas message to the country."Let us vow never to celebrate another Christmas in chains," Mandela said, speaking at his home in the nation's largest black township of Soweto, south of Johannesburg.

He noted ANC President Oliver Tambo, who returned to South Africa Dec. 13 after three decades in exile, would be meeting President Frederik de Klerk for the first time Monday on a "courtesy visit."

"The South Africa so many have sacrificed so much to achieve is within sight," Mandela said, referring to the ANC's fight against white minority rule, de Klerk's 11 months of racial reforms, and preliminary talks between the ANC and Pretoria on ending apartheid.

"Together let us walk this last, long grueling mile to reach a non-racial, non-sexist society . . . where all forms of racial discrimination are abolished," he said.

The 72-year-old Mandela, released from prison Feb. 11 after more than 27 years, said his own first Christmas in jail was "very miserable."

But Mandela said that despite a year of factional black violence that has killed some 3,000 people and threatened to derail the talks between the ANC and the government, he was confident of a peaceful future.

He also repeated ANC predictions that the splintered black opposition could soon begin the process of unification.

"We have confidence in the wisdom and good sense of the majority to share the hope with you that the New Year will bring all of us nearer to a situation of justice and peace for all the people of our country," Mandela noted.

De Klerk, facing a surge of black impatience over the pace of racial reform, last Tuesday in his own Christmas message attacked the ANC for fanning "the flames of confrontation."

The ANC had issued Pretoria an ultimatum two days before to push through certain reforms before the end of April 1991 or face a possible suspension of the preliminary talks on ending white rule.