Authorities say 54-year-old Ronald Fischman was attacked late Tuesday night at his residence on the 200 block of East Phil Ellena Street.
"It's had a devastating impact on the congregation," said David Pivar, Mishkan Shalom president.
Fischman was a long-term member and cantor at Mishkan Shalom synagogue in Roxborough.
Around 11:30 p.m. Tuesday night, police say 33-year-old Jonathan Williams, Fischman's former houseguest, broke into the home and made his way to a second floor bedroom.
Police say Fischman saw the suspect and confronted him and that's when Williams stabbed him in the neck and back then ran off.
Williams was arrested after he returned to the scene. He now faces murder and related offenses.
Police say Williams broke in looking to kill his boyfriend who Fischman was permitting to live there.
"He was a man of very modest means and yet he opened his home to two people who had even bigger financial struggles, as I understand it," said Pivar.
The Mishkan Shalom synagogue is shocked and deeply grieved. Members will say prayers for Fischman and his family at Friday's Yom Kippur services.
"People in the world, who may have violence or mental or emotional issues that they're dealing with. Things happen that we have no control over. Ron was who he wanted to be right up to the end of his life," said Rabbi Shawn Zevit, Mishkan Shalom.
Fischman was extremely active in his synagogue. He leaves behind an 8-year-old daughter and a 12-year-old son, whose bar mitzvah was set to take place in two weeks.