Oxford University Press Blog: “Idioms, especially if we add proverbs and familiar quotations to them, are a shoreless ocean. Especially numerous are so-called gnomic sayings (aphorisms) like make hay while the sun shines, better safe than sorry, and a friend in need is a friend indeed. Their age is usually hard or even impossible to determine. Since most of them reflect people’s universal experience, they may be very old. In contrast, such undecipherable phrases as kick the bucket, put a spoke in someone’s wheel, or cut the mustard are fairly recent. At least they presuppose the existence of buckets, spokes, wheels, and the cultivation of mustard.  (This type of reasoning is called relative chronology and sometimes yields useful results.)…”