In Falluja, known as the City of Mosques and a one-time bastion of revolt against US forces, Sunni Muslim spiritual leaders made clear there would be no repeat of the boycott of January's election, which left their sect marginalised.
In the Shia city of Najaf, preachers reminded the faithful that only voting on Thursday would ensure that the long-oppressed community would retain the upper hand.
Across the sectarian divide there was hope the parliament, the first fully empowered body since US forces overthrew Saddam Hussein nearly three years ago, may finally mean the departure of those troops.
Some clerics appealed for the release of Western hostages, including four - two Canadians, a Briton and an American - whose kidnappers have threatened to kill them on Saturday unless all prisoners are freed from Iraqi jails.
Others urged Iraqis to forget the trial of Saddam and concentrate on the election issues at hand - the economy, public services, sectarianism and the state's fight against violence.
Some clerics infused their sermons with messages of support for specific parties and lists - some subtle, others less so.
But most simply urged Iraqis to cast their ballot, some as a religious duty.
"Consider my words as a fatwa," Shaikh Abd al-Sattar Athaab told more than 1000 worshippers at the Raqeeb mosque in Falluja, where US troops crushed a Sunni uprising in November 2004.
"You must not vote for your tribal leaders or preachers, whom you very well know. You should vote for lists which consist of people from various sects - Shia, Sunnis, Kurds and Christians"
Shaikh Abd al-Sattar Athaab,
"Those who disobey it will be held to account under Islam. First, you must participate in the elections. Second, you have to vote for a list which really represents the people," he said.
Sunni leaders urged supporters to vote in force to allow their once dominant community to punch at its full weight in the 275-seat parliament.
Less than a year ago, Falluja was a ghost town on election day on 30 January as those of its population not displaced by the fighting had boycotted the polls - partly out of anger at the group's lost influence with Saddam's fall, and partly out of fear of reprisals by fighters.
"You must not vote for your tribal leaders or preachers, whom you very well know," Athaab said.
"You should vote for lists which consist of people from various sects - Shia, Sunnis, Kurds and Christians."
Support for Allawi
That appeared to be a veiled pledge of support for former interim prime minister Iyad Allawi, a secular Shia whose cross-sectarian coalition is posing a threat to the Shia Islamist-dominated government.
The support is remarkable considering Allawi oversaw the assault on Falluja, but it is in line with the support he has won from Sunnis for his tough line on violence, especially by pro-government militias.
Worshippers were urged to get
out and vote
In Najaf, one imam called for a peaceful final campaign week.
"We're against mutual accusations and against violations of the electoral process," said Shaikh Sadr al-Din al-Qabanji, a prominent member of the Supreme Council of Islamic Revolution in Iraq (SCIRI), most powerful of the parties in the Shia bloc which won a majority at January's election.
He cited voting as "a way to liberate Iraq from the occupation" and also hinted that Shia - marginalised under Saddam - were in no mood to see their current power diluted.
Hostage release urged
Besides the election, influential Sunni cleric Shaikh Ahmed al-Samaraie used his sermon to call for the release of the Western hostages.
"I ask those who have an influence ... to release these hostages. I understand they are in the hands of one of the groups that are defending Iraq and Islam," he said at the Abu Hanifa mosque, one of main Sunni places of worship in Baghdad.
"We don't want to lose people while we are in misery."