Supposedly, that being brave is not the same as going looking for trouble and that even king's get scared. There was before that the lesson about the circle of life and how a king must respect all creatures but there is no evidence that Simba actually learned it at that time, so I'd say it was that one about bravery which he was thought after the incident at the Elephant Graveyard.
There wasn't a moral lesson in Simba's nightmare. Simba was just comparing his father (Mufasa)'s death at the paws of Scar toward his "possible" death at the paws of Kovu.
Mufasa is Simba's father.
Mufasa, voiced by James Earl Jones, in Disney's 1994 The Lion King.
Simba as a cub dreamed of being king. His father, Mufasa, was soon killed by his evil uncle Scar. Scar tricked Simba into leaving the pridelands so he could become king. Scar told all the lionesses that Simba was killed along with his father. Simba grew up with Timon the meerkat and Pumbaa the warthog. Nala, Simba's childhood friend, found Simba while hunting. She explained the terrible condition that the pridelands were in because of Scar and convinces Simba to return. They return and overthrow Scar and Simba becomes the new king.
His father dies after saving him from a stampede of wildebeest, and as he cries over the father's body, his uncle convinces him that the father's death is his fault and that even his mother might not understand. Simba asks what can he do, and the uncle tells him to run far away and to never return. And so Simba left immediately.
There wasn't a moral lesson in Simba's nightmare. Simba was just comparing his father (Mufasa)'s death at the paws of Scar toward his "possible" death at the paws of Kovu.
Mufasa is Simba's father.
Simba's Father is Mufasa!
Mufasa, voiced by James Earl Jones, in Disney's 1994 The Lion King.
Simba's father dies and simba runs away
Mufasa
Mufasa
Mufasa and Simba
Mufasa'
Simba's father, also known as Mofasa,
Simba as a cub dreamed of being king. His father, Mufasa, was soon killed by his evil uncle Scar. Scar tricked Simba into leaving the pridelands so he could become king. Scar told all the lionesses that Simba was killed along with his father. Simba grew up with Timon the meerkat and Pumbaa the warthog. Nala, Simba's childhood friend, found Simba while hunting. She explained the terrible condition that the pridelands were in because of Scar and convinces Simba to return. They return and overthrow Scar and Simba becomes the new king.
His father dies after saving him from a stampede of wildebeest, and as he cries over the father's body, his uncle convinces him that the father's death is his fault and that even his mother might not understand. Simba asks what can he do, and the uncle tells him to run far away and to never return. And so Simba left immediately.