The role of the writer is not to say what we can all say but we are unable to say.
There are countless reasons why so many people are unable to make their voices heard. Perhaps social restrictions bind a person. Consider the character Celie in The Color Purple. During the early years of her life, she was unable to have her voice heard because she was a poor, black woman. Author Alice Walker gave a voice to all women like Celie, women who had been historically—and even in current times—suppressed.
Likewise, Jean Sasson gave voice to oppressed Saudis in her novel, Princess. Likewise, take the dramatic case of Harriet Beecher Stowe, who in writing Uncle Tom’s Cabin, an exposé on slavery in pre-Civil War America, inspired a country to change. Abraham Lincoln famously said of Stowe and her work, “So this is the little lady who started this great big war.” These authors speak for those who were “unable to say.”
There are many reasons to write, ranging from recording personal memories, offering advice, creating poetry, or documenting a historical era. All of these reasons are important. As Nin says, though, one of the unique and powerful tools a writer holds is the ability to speak for the oppressed, the disenfranchised, or those similarly unable to have a voice in society.
One word for mastery: Consistency.