Former US president Bill Clinton has delivered a clear message to Northern Ireland politicians still struggling to take the final steps in the peace process - finish the job.
On a one-day visit to the region, the statesman said the region's journey from conflict had inspired the world, but stressed more progress was still needed.
His comments come at a time when relations among parties in Stormont's mandatory power-sharing executive are at a low ebb, with a collective failure to resolve long-standing issues regarding parades, flags and, most crucially, the toxic legacy of the Troubles.
Addressing a crowd, many of them schoolchildren, in the Guildhall Square in Londonderry, Mr Clinton urged the current generation of leaders to press for consensus.
"You have to finish this, you have to be free, these children have to have a future," he said.
Mr Clinton added: "The most important thing is that you finish the job, that you free yourselves of the past so that you can embrace it and be proud of it and not be imprisoned by it."
The former president began his day-long visit to Northern Ireland by crossing a symbolic peace bridge in Derry.
Mr Clinton walked across the footbridge linking the nationalist City side of the River Foyle with the unionist Waterside alongside former SDLP leader and Nobel Laureate John Hume and his wife Pat.
Tonight in Belfast, he officially opened a leadership institute named after him at Queen's University.
Delivering the inaugural William J Clinton leadership lecture to around 150 guests from the worlds of academia and industry, he insisted the peace process had set an example for conflict resolution efforts around the globe.
In between his engagements in Derry and opening the new institute at Queen's, Mr Clinton met First Minister Peter Robinson and Deputy First Minister Martin McGuinness at Stormont to discuss the current challenges facing the power-sharing institutions.
Last week the Stormont Executive was on the verge of collapse when Democratic Unionist leader Mr Robinson threatened to resign after details of an agreement the UK Government had struck with Sinn Fein to deal with on-the-run IRA suspects became public.
While Prime Minister David Cameron's announcement of a judge-led inquiry into the controversy staved off Mr Robinson's departure, the episode was indicative of the capacity of Northern Ireland's past to de-stabilise the present and prevent progress in the future.
A talks process aimed at addressing the outstanding problems facing the region chaired by former US diplomat Richard Haass ended on New Year's Eve without a breakthrough.
A blueprint proposed by Dr Haass remains on the table but the leaders of the five main parties are no closer to reaching consensus on the proposals - and arguably further away after last week's crisis.
During his speech to a crowd in excess of 1,000 in Derry, the former president paid tribute to Mr Hume's efforts to secure peace.
But he said those still involved in the process needed to press on to overcome difficulties.
"This economy is coming back, we need to get this show on the road," said Mr Clinton.
"So I implore you, for the sake of the young people, and all those who did so much, like John, for so long - finish the job.
"This is Ash Wednesday so permit me just one reference to scripture. Often at the funeral of good people the wonderful verse of scripture is cited from St Paul - 'I have fought the good fight, I have kept the faith, I finished the course'.
"Well, you fought a good fight and I can look in your eyes and see you have kept the faith - you have not finished the course."
Bringing his remarks to a close, Mr Clinton told the people of the city his heart would always be with them.
"You have given me one more day in Derry I will never forget," he said.
On his fifth visit to Derry, Mr Clinton also helped launch a book on peace-making produced by the University of Ulster.
The 67-year-old was heavily involved in the peace process when he was president, especially in the run-up to the signing of the historic 1998 Good Friday Agreement.
He first visited Northern Ireland in 1995.
Mr Hume said the latest visit of the former president was an "incredible honour" for his city.
"I have known Bill Clinton for 22 years and I have met him every time I travelled to Washington, and I have always had the greatest admiration for him," he said.
"I am deeply appreciative for all the work he has done to help Northern Ireland, in spite of all the difficulties during his time in the Oval Office.
"Bill Clinton had economic difficulties and international difficulties to deal with during his administration, yet he gave so much time to Northern Ireland and the peace process.
"Pat and I are delighted that Bill Clinton is here in Derry, a town and its people transformed by peace and which we are all so proud of."
Mr Clinton was afforded an overwhelmingly positive response by the cheering crowds in Londonderry.
The only negative incident came when a lone dissenter briefly shouted out comments about the Iraq conflict.
Derry native Mr McGuinness was one of a number of politicians who attended the event in the Guildhall Square.
The Sinn Fein Assembly member said the visit of Mr Clinton was "hugely symbolic" and thanked the former president for engaging "emotionally and intellectually" in the peace process.
He also rejected any notion things had gone backwards politically since Mr Clinton's last visit in 2010.
"I think president Clinton understands how this place has changed," he said.
"If you cast your mind back to before he was president of the United States when there was conflict on our streets, when there were all sorts of incidents occurring, and (compare it to) what is happening now - we are an island of peace."
At the start of the event in the Guildhall Square, University of Ulster vice-chancellor Professor Richard Barnett announced that the institution had raised the £3 million required to secure a permanent endowed chair of peace studies.
The professorship at the university's Magee campus in Derry will be named after Mr Hume and Tip O'Neill, the late speaker of the US House of Representatives who was a long-time advocate of the Northern Ireland peace process.
Donations from sources including the International Fund for Ireland and the American Ireland Fund helped the university raise the money to support the position.
The appointed professor will work out of UU's International Conflict Research Institute - INCORE.