Former members of Good Shepherd Roman Catholic Parish near Mount Vernon have decided to take the offensive in their four-year battle with the conservative bishop of Arlington.

At a meeting in a nearby Episcopal Church, the dissident Good Shepherd Community for Shared Responsibility, voted unanimously last week to continue their struggle with Bishop Thomas J. Welch and to offer a haven for other disgruntled Catholics throughout the area.

The dissendent group, which, broke with the bishop over the question of lay participation in the parish, adopted a position paper commiting themselves to "active evangelizing of the unchurched or the 'underchurched' who cannot find spiritual nourishment under the current diocesan leadership."

Divergent views over what the role of the [WORD ILLEGIBLE]should be are at the heart of the Good Shepherd dispute, which has reached all the way to the Vatican and back.

When the parish was a part of the Richmond Diocese and under the leadership of the Rev. Thomas Quinlan, an elected parish council made and carried out decisions involving every aspect of parish life except those specifically reserved to the clergy by canon law.

Lay committees planned everything from liturgies to finance campaigns to the religious education of both children and adults - all under the authority of the Second Vatican Council's mandate to involve lay persons more significantly in church life.

Then Arlington was made a separate diocese and Welsh, known to be conservative, was appointed bishop. Quinlan, whose progressive style had become equally well known, was returned to Richmond.

Some parishioners bridled when the priest who replaced Quinlan reclaimed some of the functions and roles that lay members had become accustomed to filling.

Instead of accepting the directives of their new priest and bishops - as Catholics had done for centuries before the Second Vatican Council - some Good Shepherd members dug in their heels, and mobilized to fight as the Good Shepherd Community for Shared Responsibility, (GSCSR).

Today, while defiance of bishops' authority is not exactly commonplace in the church, similar confrontations have erupted in a number of dioceses. The current issue of the National Catholics Reporter, lay-edited liberal Catholic weekly, reports a number of instances:

In Kansas City, Catholics in a motorcade of 100 cars picketed. Bishop John J. Sullivan to protest his announced transfer of their pastor of 21 years, Magr. Vincent Keamey, 60. Unlike Good Shepherd, Keamey's 6,000-member parish is one of the most conservative in the city.

In Battle Creek, Neb., with a parish population of 770, 600 persons signed a petition demanding that Archbishop Daniel E. Sheehan of Omaha rescind the transfer of their pastor, the Rev. Kevin Kraft, the fourth priest in a row to be transferred after a two-year stay.

In Charleston, S.C., the Adrian Dominican Sisters threatened to pull their entire order out of the diocese because Bishop Ernest L. Unterkoefler without warning dismissed three of their number from diocesan posts for reasons they said "cannot be substantiated."

Canon law and tradition give bishops absolute authority over assignment of priests and other church personnel. In the spirit of the reforms of Vatican II, the American bishops 10 years ago established due process guidelines to handle grievances of persons who believe they are treated unfairly. But the implementation of the guidelines is optional with each bishop.

The Arlington diocese has no grievance procedure.

The Virginia dispute has been long and bitter, marked by several futile efforts at reconciliation. In 1976, the Vatican agreed to step in an attempt to arbitrate - probably an unprecedented intervention in what the Holy See normally considers the sacrosanct affairs of a diocese.

Last December, the Vatican urged both parties to go back and make "several effort" to reconcile their differences. The first tentative steps were taken at a meeting on Jan. 3, with both parties indicating good faith and willingness to enter into continuing dialogue.

There have been no meetings since and none appears likely in the future. On the contrary, the exchange of correspondence between the parties reflects increasing acrimony.

Welsh has declined to meet the dissidents without the priest he assigned to the parish, Rev. Frank E. Mahler, and members of Mahler's loyalist parish council present, as they were at the Jan. 3 meeting. "That way we can all hear the same thing at the same time and avoid some of the possible confusion that might develop because of separate meetings," the bishop wrote to George Souza' who heads the dissident GSCSR.