( CNN ) Books , filled with prayers for peace , splattered with blood . Sacred vestments shredded by bullets and knives . Lifeless bodies in the sanctuary . The rabbis had gathered to ask God to bestow blessings upon their troubled land . Their prayers were interrupted by two men wielding butcher knives and a gun . An Israeli police officer and four rabbis were killed , including an American whose family is considered `` rabbinic royalty . '' Combined with the site of the slaughter -- a synagogue in West Jerusalem -- the targeting of rabbis struck at the soul of Jews around the world , several Jewish leaders said Tuesday . `` This is an attack on all of us , '' said Rabbi Shmuel Herzfeld , who leads Ohev Sholom Synagogue in Washington . `` Any terrorist attack is a horror . But to attack people while they are engaged in prayer , are talking to God , is a new low . '' In fact , both sides in the seemingly endless fight between Israelis and Palestinians have attacked people at prayer . In 1994 , a Jewish extremist murdered 29 Palestinians worshiping in Hebron . In 2002 , Palestinian extremists attacked a Passover Seder in Natanya , killing 30 . Like those assaults , Tuesday 's murders threaten to ignite another inferno of unholy violence . Palestinian Authority President Mahmoud Abbas condemned the attack , but Hamas and other Palestinians praised the terrorists , identified by police as two cousins from East Jerusalem . Israeli Prime Minister Benjamin Netanyahu 's office vowed to `` respond with a heavy hand '' to the killings . The attackers , identified as Ghassan Abu Jamal and his cousin Udayy Abu Jamal , were killed by police responding to the synagogue assault , authorities said . Sami Abu Zuhri , a spokesman for Hamas , linked the attack to the discovery Sunday of a Palestinian bus driver hanged in his bus not far from the synagogue where the rabbis were killed . But relatives of the terrorists told The New York Times the men were motivated by Israel 's recent closure of Jerusalem 's Temple Mount/Noble Sanctuary compound , a site holy to both Jews and Muslims . The site has since been reopened , but the dispute has fueled small-scale attacks by Palestinians that have killed six Israelis in recent weeks . In the United States , the horror of Tuesday 's terror attack unified Jews across the political spectrum , even those who sharply disagree with Netanyahu 's handling of the Israeli-Palestinian crisis . In an editorial , the Jewish Daily Forward said the frustration of Palestinians `` living under occupation '' is understandable . But killing innocent men at prayer is morally indefensible , the newspaper said , noting that the synagogue is in West Jerusalem , not in `` contested territory . '' Killing innocents anywhere is detestable , Jewish leaders said Tuesday . But there is something especially heinous about killing people while they pray . `` We look on our ministers , priests , rabbis and mullahs as intermediaries between ourselves in the divine world , '' said Peter Machinist , a professor of Hebrew at Harvard University . Within the slain rabbis ' ultra-Orthodox tradition , respected rabbis are assumed to have a `` hot line to heaven . '' `` So an attack on them is a little closer to being an attack on God , '' Machinist said . The four rabbis killed were : Avraham Shmuel Goldberg , 58 ; Aryeh Kopinsky , 43 ; Moshe Twersky , 59 ; and Calman Levine . Goldberg was a dual British-Israeli citizen , and the other three were U.S.-Israeli citizens . `` This was an attack by Palestinian terrorists of pure evil and would have been utterly deplorable wherever , whenever it had occurred , '' said Rabbi Jonathan Sacks , the former chief of rabbi of Britain . `` But for this terrorist attack to occur in a synagogue , deliberately targeting innocent Jews deep in prayer , is something that strikes at the soul of Jewish people around the world . '' Obama condemns 'horrific ' Jerusalem terror attack . The Muslim Political Affairs Council also condemned Tuesday 's attack . `` We strongly believe that houses of worship should be a sanctuary for all people , not a place of violence as we regretfully witnessed today . Islam commands its followers to protect houses of worship , '' the group said in a statement on Twitter . Moshe Twersky , originally from Boston , comes from an almost Kennedy-like clan of respected scholars and rabbis . His father , Rabbi Isadore Twersky , was a world-renowned expert on Jewish theology and founding director of Harvard 's Center for Jewish learning . Twersky 's maternal grandfather was Rabbi Joseph Soloveitchik , a philosopher and professor at Yeshiva University who was considered one of the most important minds in Modern Orthodox Judaism . `` It 's a very prominent family in Jewish life , in Jewish scholarship , in Jewish theology , '' Machinist said . Herzfeld said Soloveitchik was responsible for training thousands of rabbis who passed through Yeshiva University in New York , where his legacy still burns bright . Twersky 's brother , Mayer , teaches at the university . Family legacy aside , what makes Tuesday 's attack all the more galling , Jewish leaders said , is that the rabbis planned to engage in the very opposite of terrorism : praying for peace . `` That 's what 's so horrible about this , '' said Herzfeld . `` These people were trying to do their part to bring good into this world through their dedication to God . '' 'Grief and outrage ' at Jerusalem synagogue slayings . Other Jewish leaders noted that the rabbis likely did not expect their morning service to be interrupted by an assault . `` If you are truly at prayer , you are most vulnerable , '' said Jane Eisner , the Forward 's editor-in-chief . Worshipers are not looking around for potential terrorists ; they are focused on God . During the central prayer of Jewish services , the Amidah , it is considered sacrilegious to interrupt worshipers . `` Amidah '' means `` standing '' in Hebrew , and Jews are taught to imagine themselves standing before God , asking for his blessing , said Herzfeld . By tradition , the last prayer asks for peace in Israel . It 's unclear whether the rabbis had reached that point when the slaughter began .
Killing of rabbis strikes at soul of Jews around the world , Jewish leaders said . In the U.S. , the horror of the attack unifies people across the political spectrum . Something especially heinous about killing people while they pray , they say . Muslims also condemned attack , saying followers of Islam must leave places of worship .