Every adult shall revere his mother and his father… the Torah never commands children to revere their parents. Reverence for parents is instinctive in children; they know that ultimately they must listen to their parents – they have no choice in the matter. After we grow into adulthood and become independent, we no longer need our parents and we can choose not to respect them. Therefore, explains the Netziv, it's the adults who are commanded to revere their parents.