On September 16, 2018, Eluid Kipchoge set a new world record with a marathon time of 2 hours 1 minute and 39 seconds.
He paced 2:56/km (~4:44/mi) by the 5km checkpoint and ended up pacing even faster at 2:44/km (~4:04/mi) by the end of his 42.2km (26.2mi) race.
Kipchoge was so fast that his pacesetters couldn't keep up. And he still wants to break the 2-hour marathon.
His guiding principle in life is self-discipline (did you expect anything else?). And he has a quote that explains it strikingly, "Only the disciplined ones are free in life. If you aren't disciplined, you are a slave to your moods [and] your passions."
I don't expect myself to break any world records any time soon, but as with most great quotes, Kipchoge's is a powerful guiding principle.
If not for the discipline to act on our free will, then what are we beyond animals? How much of my desire to be a couch potato and indulge in pizza and chips all evening is driven by my baser instincts? I would be neglecting my will to be a better person.
Kipchoge's principle reminds me to stick to my race and that I can always run a little bit faster.