In act 1, scene 3 of William’s Shakespeare’s tragedy Hamlet, Polonius gives his son, Laertes, a lengthy bit of advice—what Polonius calls “these few precepts” (1.3.62)—before Laertes boards a ship that will take him back to Paris after the funeral of Hamlet’s father and the marriage of Claudius and Gertrude.
Polonius advises Laertes to keep his thoughts to himself, to think before acting, to be friendly (but not too friendly), to hold fast to his true friends, and to be wary of spending too much money on new and untested acquaintances (1.3.62–69)
Be slow to anger, Polonius cautions, but once angered, be a formidable adversary and hold to your principles (1.3.70–71). Listen to what people have to say, but keep your opinions to yourself, and take each person’s measure, but resist making snap judgments about their character and trustworthiness (1.3.72–73).
Polonius reminds Laertes to spend money only within his means and to spend his money to good purpose, not frivolously—“rich not gaudy; / For the apparel oft proclaims the man” (1.3.75–76). With this in mind, Polonius also comments on the nature of the French and says that the “most select and generous” (1.3.78) among them react well to well-dressed men.
Back to money again, Polonius tells Polonius to “Neither a borrower nor a lender be” (1.3.79), because nothing good can come of it for either the borrower or the lender, and that being a borrower or a lender can be a source of disgrace and embarrassment (1.3.80–81).
The last and most important “precept” that Polonius wants Laertes to take with him back to Paris is “to thine own self be true” (1.3.82). Polonius reasons that “it must follow, as the night the day. / Thou canst not then be false to any man” (1.3.83–84).
This bit of advice to Laertes to make up his own mind about things seems contrary to everything else that Polonius tells Laertes to do, but Polonius might assume that Laertes thinks as he does and will follow “these few precepts” as Polonius has expressed them to him.