Give me six hours to chop down a tree and I will spend the first four sharpening the axe.
I don't remember where I saw this quote recently, but it illustrates how a piece of advice can look good at first glance, fall apart when you think about it, and yet still leave you with something positive.
It was attributed to Abraham Lincoln, but that's probably one of those common internet mistakes of finding an interesting saying and giving it strength by attributing it to someone you respect. For one thing, Lincoln no doubt chopped down many trees in his youth, but I doubt any of them took him six hours. Plus, who spends four hours sharpening an axe? I don't have much experience with axes, but I know that knives are more useful with more frequent, shorter sharpenings. Follow the advice of "Lincoln," and I should think you'd end up grinding away much of your axe, and still finding it dull before the job was done.
And yet ... the point about the importance of preparation is a good one.
Maybe the moral of the story is not to dissect too thoroughly words meant to inspire and encourage. Discern the wheat and let the wind take the chaff.