It is a simple, healing phrase and, when the Beatles voiced it, much of a generation was touched. But if Kenny Dalglish wasn't listening then, he certainly isn't now. Let it be. They are not the hardest words, certainly not as tough to utter as sorry, but they are plainly beyond the manager of Liverpool.
Dalglish has always been an obdurate character but what he said of the return of Luis Suarez after his eight-match ban for racially abusing Patrice Evra brought a new edge of corrosion to his contribution to an affair which in a few days' time will give us fresh evidence of a football culture saddled with hate.
There was some hope – though admittedly it was not high – that Dalglish might draw some kind of line under the case when Suarez reappeared against Spurs on Monday, especially with his player and Evra coming face to face again at Old Trafford on Saturday.
Instead, the Liverpool manager declared: "It was fantastic for Suarez to be back – but he should never have been out in the first place."
So, it is not enough that he approved the wearing of Suarez T-shirts that scandalised so much of football outside the Liverpool enclave or expressed disbelief when asked if in any way he regretted that Evra was jeered and booed every time he touched the ball when he returned to Anfield.
Now Dalglish refuses to close the door on the issue. Indeed, he provokes a new sense of injustice, a new certainty that the dispute remains a raw, untreated sore on the face of football.
This would be a lot easier to accept if Dalglish and the ownership of Liverpool had shown the courage of their belief that Suarez was innocent and fought his conviction. They had that option but they compromised. They chose the role not of fighters for truth but victims of injustice. You cannot have it both ways, and especially not if you have the kind of resources that enable you to pay £35m for Andy Carroll.
Why didn't Suarez get his second day in court? Why weren't the finest legal brains thrown into the battle for restored justice? If it was a failure of nerve it certainly wasn't matched by any shortfall in public posturing.
The result is the certainty of new levels of open-ended hostility between the followers of the two most successful teams in the history of English football.
As the John Terry case brings abject confusion to the running of the England team, the Suarez business excites ever more fractious debate in the Twittersphere and the airwaves. Wayne Rooney's almost instant message that Suarez should have received a red card for the wild kick which landed on Scott Parker's midriff is not likely to improve the kick-off mood at Old Trafford, but then when you think about it, what was?
Most obviously, some calming words from King Kenny. They didn't have to represent surrender – only an acceptance that, by Liverpool's own decision, the matter was closed effectively when the club refrained from appealing against the ban. Closed for all but the acrid and apparently unending fall-out, this is.
Dalglish, as we have seen so vividly since the moment of his re-appointment as a manager who won three titles for the club, has the Liverpool following in the palm of his hand. It was once said of his predecessor Bill Shankly that he could have ordered his people to storm the Mersey tunnel and take Birkenhead. This may or may not be true of Dalglish's influence but there is no argument that few football men have ever come to enjoy so much sway among the supporters of their clubs.
It is certainly no mystery. Apart from being Liverpool's greatest player and a highly successful manager at the first time of asking, no one embraced the tragedy of Hillsborough more profoundly. It was something that he has carried with him through all the intervening years and one effect, we had to believe, was that it took him so far beyond the trivial fevers of a mere game. He was required to deal with the unavoidable pain of a wider world and he responded with notable compassion and care.
This is what makes his bitter, narrow stance on Suarez so dismaying to many of his most ardent admirers. Suarez is playing again and with the expectation of all that instinctive brilliance and commitment which so quickly made him one of the most arresting sights in English football.
That should have been Dalglish's emphasis on the night of his return. He should have stifled the fire and not provoked it. He should have said it was time to move on, with or without a platitude or two about racism never being condoned in one of the great institutions of English football. Best of all, he would have said: "Let it be."