Why does Reverend Skyes tell Scout to “stand up”?

Towards the end of chapter 21, Judge Taylor reads Tom Robinson's guilty verdict and Scout describes the atmosphere as having a dreamlike quality. She watches as her father gets up to leave the courtroom and feels somebody punching her arm. Scout then looks up and notices that the entire balcony of black citizens is standing up as Atticus walks down the middle aisle toward the south exit. Reverend Sykes then tells Scout,

"Miss Jean Louise,...

Towards the end of chapter 21, Judge Taylor reads Tom Robinson's guilty verdict and Scout describes the atmosphere as having a dreamlike quality. She watches as her father gets up to leave the courtroom and feels somebody punching her arm. Scout then looks up and notices that the entire balcony of black citizens is standing up as Atticus walks down the middle aisle toward the south exit. Reverend Sykes then tells Scout,

"Miss Jean Louise, stand up. Your father’s passin‘" (Lee, 215).

Reverend Sykes tells Scout to stand for her father to show respect for his valiant defense of Tom Robinson. Reverend Sykes and the rest of the black community respect and admire Atticus for defending Tom in front of the prejudiced jury, which is a challenging task. The reason they stand is to show Atticus that they appreciate and respect him for defending one of their community members. Reverend Sykes has to tell Scout to stand for her father because she is distracted and unaware of the importance of her father's groundbreaking defense.