Atticus wanted his children to grow up with sound values so that they could live decent, principled lives. He was their best teacher and guide who taught them through the example of his own life and by explaining many important aspects of life and human nature which they needed to understand.
Atticus taught Jem and Scout to be compassionate, to respect others, and to try to understand how they experienced the world. He taught them to be responsible for their own actions. He taught them about real courage and the nature of justice, and he also taught them the value of personal integrity.
Atticus knew he could not protect his children from the ugliness that would result from Tom Robinson's trial, but when they did have to deal with it, he helped them understand cruelty, racism, and ignorance and to reject it.
Jem and Scout learned many valuable lessons from their father. By the conclusion of the story, Jem had cried angry tears when Tom was so unjustly convicted, and Scout had taken Boo's hand gently to walk him home. They had learned their lessons well from Atticus and were growing up in a way that would make their father proud.