The Prince and the Pauper

In an unnamed kingdom, a good king rules justly and wisely over his subjects. However, when the king grows ill, his Captain of the Guards, seizes the opportunity to rob and terrorize the populace, all in the name of the king.One day, Mickey, Goofy, and Pluto are attempting to make money by selling kindling and snowcones, but there are few takers. Suddenly, a cart carrying Captain Pete and a cadre of weasels goes by, and Pluto chases after the cart after he sees some sausages hanging off the rear.Mickey follows Pluto to the castle gates, where a guard thinks he's the Prince, and quickly lets Mickey in.Needless to say Captain Pete sees this, and apprehends Mickey and Pluto, before the Prince hears the commotion, and demands the person Pete is apprehending be brought to him. Pete has his guards send Mickey to the main hall of the palace, but kicks Pluto outside the castle walls.Once in the main hall, Mickey and the Prince meet, and are amazed how much they resemble the other! The Prince tells Mickey how he's bored with Palace life, and hatches a 'grand idea': they will trade places, with Mickey being the Prince. The Prince convinces Mickey he will only be gone for awhile, and that by wearing a Royal Ring, it will tell people who he (the Prince) really is.Dressed in Mickey's clothing, the Prince leaves the palace, and is kicked out by Pete. Pluto isn't convinced that the Prince is Mickey, but Goofy simply assumes his friend's new mannerisms are a practical joke.Meanwhile, Mickey attempts to pass himself off as the Prince, but much of his attempts to fulfill royal duties end up in disaster.In the kingdom, the Prince sees royal guards attempting to steal food from the peasants, and attempts to intervene, only to be mocked and ridiculed. When The Royal Provisioner comes by, The Prince stops him by showing his royal ring, and begins to pass out food to the peasants. When the Provisioner brings some of the royal guards, they attempt to arrest the Prince, before Goofy spirits him away.Back at the castle, one of the weasels mentions 'the pauper' who acted like a nobleman, and had a royal ring, leading Pete to realize he threw out the real Prince previously.Meanwhile, Mickey is informed that the King is in his final moments, and wishes to speak to him. Mickey attempts to tell The King who he is, but the King just tells 'his son' to rule justly, and wisely when his time comes.After the King passes away, Pete apprehends Mickey, forcing him to do as he (Pete) says, or Pluto will be harmed.Meanwhile, news of the King's death and eventual crowning of the Prince has reached the real Prince's ears, and he has a moment of sadness that he was not there for his Father's passing. However, as he speaks aloud how he will do something about the rampant corruption in the Kingdom, Goofy soon realizes that the Prince is not his friend Mickey. Even so, Goofy is willing to help the Prince in anyway that he can. However, before they can do something, Pete and his guards appear, capturing the Prince, and sending Goofy out a nearby window.The Prince is thrown in a dungeon, with plans for him to be executed after Mickey is crowned. However, Goofy manages to sneak into the castle in disguise as an executioner, and manages to free the Prince.They soon make their way into the grand hall, where the Prince squares off with Pete, with a little help from Mickey and his friends.In the aftermath, the Prince is crowned, and narration of the story tells how he fulfilled his promise to rule justly and wisely, along with his new friends in tow.

Question: What did the King tell "his son"?
Answer: to rule justly and wisely; to rule justly and wisely