LEXINGTON — Colored lights shine from the tall evergreen on Lexington Common. Across the street, wreaths with bright red bows decorate the doors of Hancock United Church of Christ, Congregational. But inside the church’s dimly lit chapel the other night, the mood was somber.

A couple of dozen people had come for the church’s “Blue Christmas” service. Together, they sang quiet carols and lit candles for loved ones lost, for friends and family battling illness or hardship, and for their own private troubles.