SUTHERLAND SPRINGS, Tex. — Under heavy clouds and spitting rain, hundreds of people gathered at a baseball field here on Sunday to worship with the survivors of the massacre at the First Baptist Church one week ago.

Its pastor, Frank Pomeroy, fought back tears as he delivered his sermon, which emphasized the power of light to triumph over darkness. One of the victims, Annabelle R. Pomeroy, 14, was his daughter.

It was the church’s first Sunday service since a masked gunman, Devin P. Kelley, opened fire on parishioners in a methodical shooting that may have lasted as long as seven minutes.

The small church on Fourth Street remained closed on Sunday morning, so parishioners and hundreds of guests gathered under a white tent. But in the evening, the church reopened — this time as a memorial.