Is there any sin so grave that a Christian could not conceivably commit it? It might seem that the abuse of a child is the maximum sin, but such would not be acknowledged as such by the prosecution in Arusha, Tanzania, where three Roman Catholic priests, one Seventh-day Adventist pastor and one Anglican bishop are being tried for -- no less -- complicity in genocide. They are Rwandan citizens, and it is alleged that, by varying acts, they cooperated with what became, in 1994's civil war, the murder of 500,000 Tutsis by the rival Hutu tribe.

Two of the defendants, Pastor Ntakirutimana and his son, a medical doctor, are defended by Ramsey Clark, former attorney general of the United States, whose search for infamous clients may at last have been achieved. The Catholic defendants were complained about to Rome, which, it is reported, was until recently only listlessly concerned. "There has been a clear turnabout in the Catholic Church," a prosecutor now reports. "In the last few months they have done everything to facilitate our work."

But what can Rome, or the Seventh-day Adventists, or the Anglican Church, or the Catholic bishops do to stop Rwandans from engaging in genocide, or American priests from abusing children? What can be done at the civil level is obvious: cooperate with agencies that detect, overcome such obstacles as Ramsey Clarks can put in the way, and put the criminals in jail, or hang them as in Nuremberg.

But the terrible, wilting casualties multiply by 100 the pain of the deceased and the mutilated, the pain of the demoralized. Because indifference to the commandments of the religion of the priests, American and Rwandan, is indifference to the primal commandments of civilized and humane life. What has been done, and is now everywhere explored, is the violation of the word of God by professional practitioners of the word of God. The cynicism engendered is awful in implication, and the scandals can wrench the faith even of the teen-agers at St. Mary's in Dedham, except as they hew to the demands of their faith, which counsel that hope cannot be abandoned, nor spurned.