This sentence comes from "Family Instructions and Self-cultivation Language" written by Mr. Qian Decang in Qing Dynasty, which says: "A gentleman judges the beginning, understands it, and then argues."
The general idea is that in interpersonal communication, whenever money is involved, even close relatives and friends should draw a clear line and settle accounts clearly. Don't be sad after eating YaBaKui. Those who respect face must not be hooligans.
Extended data:
Qing Ma Feng's Notes: "Giving money is the hardest thing, even close relatives and friends should understand it. It is better to meet later than to be confused at the beginning. " As the saying goes, it is right to argue before you know.
It means that things related to money should not be vague, although relatives and friends should also understand. They would rather be humble to each other behind their backs than be vague at the beginning. The ancients said that "it is wise to argue before it is clear", which is a wise saying!