At 10 p.m. Monday, Rabbi Yosef Langer came home to San Francisco's Chabad House to find a parcel on the doorstep.

It bore no address, but did have some crudely scrawled Hebrew letters spelling "Baruch HaShem," which means "Blessed be the holy name." Langer was just about to open the package — but a friend caught his arm.

"He said, 'Don't touch that; it looks funny. Who put that there?'" Langer recalled.

Langer phoned the police, who arrived in a hurry. An officer also stretched his hands to grab the box, but his co-workers stopped him. They alerted the bomb squad.

It was a false alarm.

Taking all precautions, the San Francisco Police Department bomb squad roped off the entire 2900 block of Anza Street and brought in an X-ray machine. After inspecting the box and bag, they pronounced them harmless.

Inside, Langer found some clothes and assorted Judaica, including kiddush cups and tzitzit.

"It was left by some meshugah. Thank God it wasn't a bomb," he said.

"Obviously, it was from the hand of someone that was deranged. It was stuff that didn't have a connection to anything. It had no indication to whom or from whom."

After his nerves settled that night, Langer wondered if he had done the right thing. Had he overreacted as a result of heightened tension in the Jewish community after a string of notorious anti-Semitic acts this summer?

Police assured Langer he'd acted appropriately. "They thanked us for informing them," he said. "They said this is what they are there for and don't hesitate to call on them. They were very receptive."

Langer did not have to tell police about the sense of nervousness in the Jewish community. The police already knew. "They've had other calls," the rabbi said.

The bomb scare has only emboldened Langer.

"My thrust as being a Chassidic rabbi is that I have to be a more proud Jew and take a step further — not to shy away but to increase my presence."

As in the past, Langer will offer free High Holy Day services — Chabad will rent a room at the Mark Hopkins Hotel on Nob Hill.

Langer will, however, put a few extra security measures in place. "We have to have our eyes open and be alert to what is going on," he said. "We can't just be naive and say there isn't anti-Semitism in the world."