Disciples don't always kneel at the feet of their role models.
So in 2005, when a little-known US senator met one of the world's most illustrious elder statesmen, former South African president Nelson Mandela, he did not kneel. He stood tall, but bent down to shake Mr Mandela's hand in a powerful political metaphor of their common legacy.
That former senator is US President Barack Obama, who today paid tribute to the man he met just once, eight years ago: "He no longer belongs to us - he belongs to the ages."
That solitary meeting between the first black presidents of both nations was very brief. And it took place when one was a world figure but the other was not.
That day, Mr Obama actually stood up a group of people he was scheduled to meet in Washington DC, just so he could meet Mr Mandela. It was a carefully-considered decision, because as many commentators have pointed out, up-and-coming senators tread on very thin ice if they turn their backs on important folk in the national capital.
But Senator Obama was in a car en route to the scheduled meeting when he was told that a visiting dignitary had agreed to make time - albeit briefly - to meet him.
That visitor was Mr Mandela. And the whisper is that he had no idea who this US senator was, so his closest advisers had to persuade the statesman to allow him a few minutes, on the basis that the American was a rather well-regarded young man with fairly decent political prospects.
So when the news came that Mr Mandela would grant him a few moments, Senator Obama made a snap decision. He would forgo the scheduled meeting. Instead, he asked the driver of his humble Volkswagen - this was back in the days before he was chauffered around in a black armour-plated limousine with a police and Secret Service escort - to change course.
So the Volkswagen made a detour and pulled up outside the Four Seasons hotel. And as the senator got out, his driver-aide, Mr David Katz, made a last-minute decision to take his camera along as well.
In retrospect, it was a momentous decision. Mr Katz is not a professional photographer, but one of the images he shot in the hotel could be worth a lot of money one day.
In his suite, Mr Mandela apologised for not getting up. He was sitting on a comfortable armchair, his aching feet stretched out on a matching footrest. Beside his left foot was a wooden walking stick.
The tall US senator bent to shake hands with him. And as he did so, Mr Katz fired the shutter of the camera. Perhaps he didn't know that placing a person in front of a bright window reduces that person to a mere silhouette. Or perhaps he did know, and opted for a striking technique.
The Lincolnesque photograph shows Mr Obama in almost total silhouette, grasping the hand of Mr Mandela, whose paisley shirt and smiling face are beautifully lit by the lamps in the hotel room.
It was a pivotal moment in history. The first black president of South Africa, being greeted by the man who would later become the first black president of the United States.
The New York Times reported in June this year that one copy of that momentous photograph is on display in the Mandela Foundation office, while another is in Mr Obama's Oval Office.
Had Mr Mandela's advisers not told him that it would be worthwhile meeting the senator, the pivotal moment would not have taken place.
Had Mr Obama not taken the snap decision to ditch his scheduled meeting to pay tribute to the distinguished visitor, he would always have regretted it.
And if his aide, Mr Katz, had not reached back into the Volkswagen to take his camera, we would never have had this single image of the day history was made between two presidents who not only made political history, but who each won the Nobel Peace Prize as well.