Church of Scotland Moderator the Rt Rev John Chalmers called for people to go to vote “with cool heads and calm hearts”.
And he suggested posting a selfie with someone who voted the opposite way and replacing Yes and No twibbons with a “One Scotland” symbol on Facebook profile pictures.
Mr Chalmers said: “We cannot let ourselves be defined by which side we are on. We must make sure that post-referendum there is no us and them, but only us.”
His message echoes the appeal by Margo MacDonald, spelled out at her memorial service, for people to come together once the referendum was over and demonstrate a “unity of purpose”.
Mr Chalmers said the actions of political leaders in the first 72 hours after the result could be crucial in setting the tone for how people will respond to the outcome.
Amid fears that, whatever the outcome, Scotland could be left a divided nation, he said the leaders of the winning side should host an event with the key figures from the opposing camp to work on a strategy for the country’s future.
He called on senior figures on both sides of the debate to be clear in both their words and their actions that the issue had been settled democratically.
“The campaign with the majority should announce a post-referendum event inviting the main players on both sides to discuss a shared strategy for delivering the settled will of the Scottish people,” he said.
Mr Chalmers is due to preach at a service at St Giles’ Cathedral on Sunday morning when politicians from both campaigns are expected to take part and signal their commitment to a unity of purpose.
Representatives of other churches and other faiths have been invited to join in the service, which starts at 11.30am.
Labour’s Douglas Alexander and the SNP’s John Swinney are due to read the lessons, but Mr Chalmers said given all that would be happening in the aftermath of the referendum, it would not be clear which other politicians would be able to attend until the last minute.
But he urged people to prepare emotionally for the result as soon as they had voted today. He said: “People on all sides recognise we are making a huge decision about our nation, but it is one that will affect people personally as individuals.
“So tomorrow morning some people will feel quite bereft and others will feel elated.
“It’s time for all of us to prepare for the result emotionally. I’m saying to people: cast your vote – it’s important everybody participates and therefore everybody has a sense of ownership in the outcome – and walk away and leave your passion at the ballot box and replace it with preparation for the result with the mindset you are going to participate in the ongoing process even if it’s not the result you wanted.”
Some churches were open today to allow people a place for quiet reflection and prayer before casting their vote.
Mr Chalmers said social media had been a source of some of the worst tensions during the campaign, but it could now be used to try to repair some of the damage done.
“Voters can remove their Yes/No affiliations from their profile images and replace them with a shared symbol of unity, such as the One Scotland badge available on the Church of Scotland Facebook page.
“And politicians, campaigners and voters could post selfies of themselves with someone who has voted the opposite way and share them.
“Both Yes and No sides could also agree a number of joint hashtags to promote magnanimity and a celebration of the democratic process.
“These are very simple things. No-one should imagine they are quick fixes to people’s emotional wellbeing but they will start to assure people that the effort which went into campaigning is now going into working together. I have every confidence the Scottish people will do that.”
Harry Potter author JK Rowling – who became a target of cyber abuse after declaring her support for No – appealed for Scots to be friends regardless of the outcome of today’s vote.
She posted a message on Twitter urging fans to put aside differences. She said: “My head says no and my heart shouts it – but whatever happens I hope we’re all friends by Saturday.”
Mr Chalmers said Margo’s message of unity was exactly what the Church was trying to get across.
At the memorial service for the independent Lothian MSP, who died in April, her husband, Jim Sillars, said: “There were times she came home from the Scottish Parliament, expressing concern about what she described as the palpable air of bitter antagonism generated in some debates.
“She knew only too well that this nation is divided on the issue of independence.
“We discussed this division, and what these people will do with the sovereignty they hold in those 15 hours between 7am and 10pm on September 18.
“She so desperately wanted us to hold on to it. But, at one minute past 10pm, whatever the result, she wanted those divisions to end and this nation seek a unity of purpose.”
And he passed on Margo’s plea for the exercise of mutual respect as “a civilised corrective to uncivilised abuse”.
Mr Sillars said today: “Margo recognised that a referendum would divide opinion and she hoped, and urged, that once the people decided, all of us would put aside our differences and work together for the benefit of all of Scotland.”
The Moderator endorsed Margo’s unity plea. He said: “We have to be able to disagree without being disagreeable. We have to be able to live with our neighbours even if we voted differently.
“We cannot define ourselves by the way we voted, but we have the opportunity to define ourselves by how we respond to the result.
Get ready to accept the will of the Scottish people – and that will be best done by setting passions aside. Whatever the outcome we will need to be ready to work together.”