"We are shaken, but we are not forsaken," the church said in a statement.
Central Reform Temple announced cancellation of Sabbath Eve service on its website, citing emergency conditions in Boston.
"We are determined to gather together for worship and mutual support as soon as possible," the temple said.
Instead, the Friday service was scheduled for Sunday morning at nearby Emmanuel Church.
Temple Israel opened its doors to the congregation of Trinity Church for a 10:30 service Sunday. Trinity is in Copley Square, near the marathon finish line, and it remains closed.
Trinity's congregation filled the sanctuary at Temple Israel, which can seat about 900 people, said Rabbi Ronne Friedman. The clergy and staff were surprised in the best possible way that so many people showed up.
The synagogue, he said, was honored to host Trinity in an hour of need.
"It was beautiful, moving," he said. "And it was a reminder of the deep bonds that exist between us. It reminded us all that our proximity is not just geographical.
"After the trauma of the past week, we are in proximate relationship with one another spiritually and psychologically. I think we all very much felt it was one Boston."
Imam Talal Eid of the Islamic Institute of Boston said Muslims were participating in interfaith prayers.
"I know that in all mosques, there have been prayers said for the victims," he said.
The holiest day of the week for Muslims is Friday, but several Boston mosques were closed then because of the lockdown during the massive manhunt for one of the bombing suspects. The same was true for synagogues, which hold services Friday evening and on Saturday.
With Monday will come a new week. Officials have called for a moment of silence at 2:50 p.m. Then, the bells will toll in Boston and the entire state of Massachusetts. And everyone will stop to remember.