A beaming Vice President Bush and his wife Barbara Bush looked on yesterday as Paula Hernandez-Rendon, a Mexican-born, 25-year household employe of the family, became a naturalized U.S. citizen in ceremonies in federal court here.

"All of a sudden . . . she surprised us, and did it by herself," said Barbara Bush after the half-hour swearing-in at the U.S. District Court's large ceremonial courtroom. Rendon, accompanied by a Secret Service agent, joined 56 other foreign-born nationals in the proceedings.

Shirley Green, a spokeswoman for the vice president, said that Rendon began working for the family when the Bushes lived in Houston and that she had helped bring up all five Bush children.

"She's a real member of the Bush family," Green said. "To call her the housekeeper doesn't really say it."

"Welcome to your country," the vice president said after the group had pledged allegiance to the United States. "This land is now your land . . . .

"Freedom is yours and mine. We are free to pursue our dreams and use our talents to make something of ourselves, our families and our communities. We who live in freedom don't live in a perfect society because we're not perfect. But freedom gives us a second chance.

"We're free to make mistakes and learn from them, and as a result grow wise."

U.S. District Judge Harold H. Greene, also a naturalized American, presided over the ceremony. Greene, born in Frankfurt, Germany, became a citizen in 1944 while serving with the U.S. armed forces in World War II.

"On behalf of the court and the government and the people of the United States, I welcome you and I congratulate you," Greene said. "I also congratulate the United States. Like millions before you, you established a relationship beneficial both to you and to this nation . . . .

"All we need to ask is, where is it difficult to get exit visas? Where are walls built to keep people in? Where is it dangerous even to communicate with the outside?" Greene asked.

"When people are free to come and go as they please, America and its freedom are most often their destination. There can be no greater vote of confidence, nor more meaningful election."