Barack Obama shows his class on the Humans of New York page

As he admits, he "wasn’t getting a lot done" at the time and he "got whooped" when he ran for Congress, which made him think that politics wasn't "what I was cut out to do".

However, amid all the strain his work was putting on him and his family, he got through it by realising that "it’s about the work".

He pointed out that rather than worrying about how he was doing, which he said leaves him with a feeling of frustration, he concentrated on the work itself - that way "you’ll always have a path".

In other words, don't give up as "there’s always something to be done".

A hint to Donald Trump of what the presidency will be like? A plea to Hillary to keep on going?

Who knows? But it has received a lot of love from readers.

If you can't read the Facebook post above, click here.

Here is the text of the Facebook post in full:

"I first ran for Congress in 1999, and I got beat. I just got whooped. I had been in the state legislature for a long time, I was in the minority party, I wasn’t getting a lot done, and I was away from my family and putting a lot of strain on Michelle.

"Then for me to run and lose that bad, I was thinking maybe this isn’t what I was cut out to do. I was forty years old, and I’d invested a lot of time and effort into something that didn’t seem to be working.

"But the thing that got me through that moment, and any other time that I’ve felt stuck, is to remind myself that it’s about the work. Because if you’re worrying about yourself — if you’re thinking: ‘Am I succeeding? Am I in the right position? Am I being appreciated?’ – then you’re going to end up feeling frustrated and stuck.

"But if you can keep it about the work, you’ll always have a path. There’s always something to be done."