Michael Donald Bray, a Bowie house painter and fervent opponent of abortion, went on trial today denying that he had any role in the bombing of 10 abortion clinics and related facilities from Delaware to southern Virginia in 1984 and early this year.

Prosecutors in opening statements asserted that Bray participated directly in at least two firebombings with alleged coconspirator Thomas Eugene Spinks and helped assemble explosives for others. Spinks has pleaded guilty to conspiracy and related charges in the bombings.

A third defendant, Kenneth William Shields, 34, of Laurel, is scheduled for a separate trial June 3.

Charged with conspiracy and possession of unregistered explosive devices, the 32-year-old Bray, who has pleaded not guilty, sat in federal court here today as his attorney, Robert Muse, called him a man of the "finest Christian values imaginable" and prosecutor Robert J. Mathias described him as so "frustrated" with the ineffectiveness of peaceful antiabortion demonstrations that he resorted to violence.

"This is not a case about abortion," Mathias told the jury of seven men and five women selected today before U.S. District Judge Alexander Harvey II. " . . . . This is a bombing case . . . . We ask you to focus on the evidence and not be led astray by any red herrings about abortion."

In his opening statement to the jury, Muse attempted to shift attention to Spinks, saying the 37-year-old Bowie roofer has "cut a deal with the government," trading his testimony for a guilty plea and recommendation for a light sentence.

Spinks is "unreliable, untrustworthy . . . and completely sullied" by the arrangement, Muse argued. In contrast, he said, Bray is "a person of extraordinary virtue and goodness . . . . He is not a criminal."

Mathias said evidence in what is expected to be a two-week-long trial will show that Spinks and Bray drove together to Dover, Del., and Norfolk in early 1984, setting off firebombs at abortion clinics in both cities.

Thereafter, Mathias said, Bray became a lay copastor of a splinter church that had broken from the Grace Lutheran Church in Bowie. He was concerned "about church reaction if he was caught . . . and decided to move into the background," providing only logistical and planning assistance for eight more bombings carried out by Spinks.

In opening testimony, Forest L. Parham, a Norfolk Fire Department investigator, said that when he arrived at the firebombing of the Hillcrest Clinic in that city at 3:15 a.m. on Feb. 17, 1984, he found a large flat board with "Hillcrest Murder" printed on one side and "A.O.G" on the other.

A.O.G. stands for "Army of God," Mathias said. During the rash of bombings in 1984, a male caller saying he was a member of the Army of God telephoned news agencies claiming responsibility for several of the blasts. The bombings, most of them at night, did extensive damage to clinics and adjacent unrelated offices, but no injuries were reported.