Polonius is King Claudius's chief counselor. He is portrayed as a sententious blowhard and sends Reynaldo to spy on his son Laertes while he is in France. In act 1, scene 3, Polonius offers Laertes several pieces of advice before he departs for France and hopes that his son will follow his precepts and behave accordingly. The first piece of advice Polonius gives to Laertes concerns the importance of controlling his tongue and maintaining his composure. Polonius tells Laertes,

Give thy thoughts no tongue,
Nor any unproportioned thought his act. (1.3.59-60)

Polonius is essentially instructing Laertes to not speak his thoughts aloud or be too quick to act upon his opinions without fully examining them. This seems like sage advice from the chief counselor which would surely benefit Laertes. Polonius goes on to tell Laertes,

Give every man thy ear, but few thy voice. (Shakespeare, 1.3.68)

Polonius desires his son to listen first and speak second, which is another wise piece of advice. He wants Laertes to value listening over speaking and encourages him to only talk when necessary. However, the audience finds this information ironic, considering the fact that Polonius does not hesitate to freely voice his opinion on matters. Polonius concludes his speech by telling Laertes,

This above all—to thine own self be true,
And it must follow, as the night the day,
Thou canst not then be false to any man. (Shakespeare, 1.3.78-80)

Once again, Polonius portrays himself as a hypocrite by instructing Laertes to be true to himself in order to never be false to anybody else. Polonius believes that following one's heart and path in life will make them honest, genuine individuals. However, the audience views Polonius as a dishonest sycophant who attempts to deceive Hamlet and does not trust his own son.