The Committee for Sensible Marijuana Policy, the group behind the ballot measure that would decriminalize possession of less than an ounce of marijuana, said Monday that it has received the endorsement of 51 clergy members across Massachusetts.

The news comes two days after the ballot measure's opponents announced that former Boston Mayor Ray Flynn mailed a letter denouncing Question 2 to 2,200 Catholic parishes across the commonwealth.

The clergy members signed a statement calling for more compassionate marijuana laws.

"We're not urging anyone to use marijuana," said Rev. Marc Fredette of Waltham's First Unitarian Universalist Parish. "But it is worse to have a marijuana policy that doesn't accomplish any of its goals, disproportionately punishes the most vulnerable members of our community, and continues to punish them even after they've served their sentence."

The Committee for Sensible Marijuana Policy also announced that it ran a full-page ad in the Berkshire Eagle Monday urging voters to support the measure.

"It's time to set the record straight," Charles Thomas, executive director of the Interfaith Drug Policy Initiative in Washington, D.C., said. "Criminal penalties for marijuana possession violate the core religious principles of justice and compassion. Religious leaders everywhere are seeing the light, and it's very encouraging that clergy in Massachusetts taking a position on Question 2 are overwhelmingly supportive."