A joint resolution passed by Congress sets aside July 22, tomorrow, as ''Rose Fitzgerald Kennedy Family Appreciation Day.'' Mrs. Kennedy, the first-born of second cousins John Fitzgerald and Mary Josephine Hannon of Concord, Mass., will mark her 100th birthday on the 22nd, a day on which Congress asks the nation to appreciate families ''with appropriate ceremonies and activities.''

Last Sunday and celebrating a week early, Rose Kennedy, with the vane of her oceanside home calmed by the weather of Irish gaiety, was at the center of a bonding that brought together most of her family of five children, 28 grandchildren and 22 great-grandchildren. The press calls it the Kennedy compound, but it is really the Kennedy parish. There a faith is kept and liturgies of public service begun by Rose Kennedy's father -- three-term congressman and two-term mayor of Boston -- remain honored by her children and grandchildren.

Congress, citing Mrs. Kennedy's ''commitment to the central role of the family in American life,'' would like the institution to be appreciated tomorrow. It should take a lot less doing in 1990 than in 1890. A century of shrinkage has occurred. Rose Kennedy was one of six children and became the mother of nine. Her father was one of 12 children; her mother was one of nine. For American families in 1990, three children is stretching it. The daguerreotypes that large families posed for a century ago were photographs of whole family trees, not family twigs with an average of 2.2 children.

Rose Kennedy remembers that her mother's having five babies after her meant that ''she didn't have as much time for me as some of my friends whose families were smaller.'' But it had an advantage: ''It made me more self-reliant and independent.''

She was to need both in her marriage to Joseph P. Kennedy, whom she met at a family gathering when she was five and he seven. Her husband turned out to invest as much energy outside the home as in, and eventually the couple led separate emotional lives.

Although she campaigned when her sons ran for office, Rose Kennedy believed that the family was best kept together by fidelity to religion. She remembered her childhood and its expressions of family-oriented faith: ''Every night during Lent, my mother would gather us in one of the rooms of the house, turn out the lights -- the better to concentrate -- and lead us in reciting the rosary. I'm sure my knees ached and that sometimes I wondered why I should be doing all the kneeling and studying and contemplating and praying. And I became understanding and grateful.''

For Rose Kennedy, attention to God was a means of attentiveness to her children, who were the core of her life. She lived according to a piety that was to brand her -- by the standards of the worldly -- a simpleton but that in the steadfastness of the heroically devout placed her among those unsung parents for whom children are a gift from God. In the 1940s, she lost one in World War II aerial warfare and one in a plane crash. In the 1960s, she lost two more to assassins. It was her faith -- sustained by the rosary, daily Mass and the sacraments of the church -- that let her accept the truth that some gifts were meant to be returned to God.

It is true that the wealth of her husband provided Rose Kennedy with nannies, cooks, chauffeurs and maids, and with so much household help why wouldn't rasing kids be a sunny picnic? If hired hands can bring relief, they can also deliver false freedom, leaving the rich to fritter away their time on life's vacuities. Except for an occasional gad to the designer dressmakers, Rose Kennedy sought and found her happiness in the time spent with her family.

The most joyous years of her married life, she recalled, came from 1938 to the early 1940s when the family was together in London and Joseph Kennedy Sr. served as the ambassador. For Joe Kennedy, the fever of his money-making days and Hollywood cavortings having passed, his wife's enthusiasm for the family was catching. The Kennedys' nurse at the time remembered the ambassador ''as a man who cared more about his children than any man I've ever seen.''

I interviewed Rose Kennedy in 1978 on a summer evening in the family sailboat with 20 others aboard. Two miles offshore, a storm blew in and, with high waves cresting higher, 19 people wanted to tack for land. One said let's go out farther. That was Rose Kennedy, 88 and calming another storm by daring its forces. Half the boat was family, and it would defy the odds together.