I believe you are referring to Atticus ordering Jem to show Scout to her room at school. Of course, Atticus does this in his loving but firm way. This order to Jem also skillfully weaves in Atticus' typical lawyerly "deal making" that respects the children's feelings yet does not undermine his authority. The "order" is actually related to the reader in a second-hand way, that is, through Scout in the second paragraph of Chapter Two:
Jem condescended to take me to school the first day, a job usually done by one's parents, but Atticus had said Jem would be delighted to show me where my room was. I think some money changed hands in this transaction, for as we trotted around the corner past the Radly Place I heard an unfamiliar jingle in Jem's pockets.