A form of prayer that was said seven times each day and practiced for centuries only by holy men and women in religious orders has been introduced as a religious exercise for lay Christians.

With the prompting of William Cardinal Baum of the Catholic Archdiocese of Washington, the National Shrine of the Immaculate Conception here has launched a program to adapt the ancient Liturgy of the Hours to spiritual needs of modern Christians.

The shrine's Liturgy of the Hours, conducted by eight nuns assigned full-time to that task, is scheduled to be adapped to programs of local parish churches in the near future, Cardinal Baum said.

The seven relatively brief prayer sessions of the Liturgy of the Hours are built around the psalms of the Old Testament, said Sister Joan Noreen, who is coodinating the program at the shrine.

The prayers are offered daily in the shrine's Blessed Sacrament Chapel, beginning with morning prayer, or lauds, at 9 a.m. and continuing through the day at 90-minute intervals.

Cardinal Baum acknowledged that "it is not realistic to think that the majority of people will be able to do this (take part in the Liturgy) on a regular basis. The average person will not be able to come to church at these time."

Nevertheless, he expressed hope that the availability of the prayers would be beneficial for those who could participate.

In addition, he explained, books now are being published in which "this kind of prayer is adapted for home use."

Adaption of the Liturgy of the Hours for the laity was one of the recommendations of the Second Vatican Council, Cardinal Baum noted.

Carrying out that task, he explained, "has been postponed because of our preoccupation with other liturgical changes," primarily those involving the mass.

Cardinal Baum characterized the Liturgy of the o Hours as an extentsion of the faithful coming together for the mass. "From the earliest days of the church there has been an emphasis on communal, corporate prayer," he said.

"To oversimplify it, one who prays remains close to God; one who fails to pray falls away from God," he said.

Cardinal Baum warned that prayer must never become an end in itself. "The life of prayer must lead to service. For a Christian, it's not a choice of prayers or action; they must be integrated. Prayer should never be used to manipulate God or to escape from life and the obligation to serve," he said.