Don't let your pride consume you because it will have unfortunate outcomes. The narrator let his pride take control and pushed Doodle too hard, ultimately leading to his death.
"It was bad enough having an invalid brother, but having one who possibly was not all there was unbearable, so I began to make plans to kill him by smothering him with a pillow."He was so ashamed of Doodle's condition and it embarrassed himso much that he wanted to kill him.He wanted to kill Doodle because he didn't want to have a brother who was not there. This led to his pride causing him to want to kill Doodle.
"They did not know that pride, whose slave I was, spoke to me louder than all their voices; and that Doodle walked only because I was ashamed of having a crippled brother." The narrator states that his pride is the only reason Doodle learned to walk. Showing that his pride made him pressure Doodle to walk.