Thirty-four imams belonging to the Islamic Supreme Council of Canada, including a handful of American members, signed the fatwa in an effort to counter misinterpretations of the Qur'an, they said.
While it has no legal teeth, the fatwa is "morally binding" for all Muslims, said Syed Soharwardy, a Calgary-based imam who founded the council.
"So if anybody is thinking that honour killing is allowed in Islam, or domestic violence is OK or misogyny is OK, we are saying no, you are dead wrong," he said Saturday in announcing the measure.
The ruling comes after a verdict was delivered last weekend in the Shafia murder trial, in which a Montreal couple and their son were convicted of killing four female relatives.
The Crown alleged three teenage Shafia sisters and their father's first wife in a polygamous marriage were killed in an effort to restore the family's honour.
The trial captured worldwide attention and cast a shadow over Canada's Islamic community, prompting many religious and community leaders to speak out against domestic violence.
For months, imams worked together to denounce honour killings and educate Muslims about the call for gender equality at the heart of their faith.
The fatwa "puts some weight" on those efforts by clearly and unequivocally refuting any interpretation of the Qur'an that would allow domestic or honour-related violence, Soharwardy said.
It's a rare step, one the 12-year-old council — which includes mosques and chapters in major Canadian cities — has taken only twice before to oppose terrorist attacks and Taliban rules prohibiting girls from going to school, he said.
With a combined congregation of roughly 10,000 people throughout the country, the organization has more clout than a single imam or scholar might have in issuing a fatwa, Soharwardy said.
The actions of one misguided family have revealed the need to take a stronger stand against domestic violence, he said.
"What happened in the Shafia home ... The crime was not committed because Islam says so. The crime was committed because that is the way they understood what they think is right," he said.
Mohammad Shafia, his son Hamed and his wife Tooba Yahya were each found guilty of four counts of first-degree murder in the deaths of sisters Zainab, 19, Sahar, 17, and Geeti, 13, and Rona Amir Mohammad, 52.
The four bodies were found June 30, 2009, in a car submerged in a canal in Kingston, Ont., in a multiple murder the Crown asserted was committed after the girls shamed the family by dating and acting out. Rona was simply disposed of, the Crown said.
First-degree murder carries an automatic life sentence with no chance to apply for parole for 25 years. Those convicted in the case have been behind bars since their arrests on July 22, 2009.
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