What is a lesson that the Logan children learn in chapter 4?

Stacey tries to get his siblings to go home but they follow him to the Wallace store. There, the Wallaces and the older Sims brothers make disparaging remarks about "little niggers" while older students from Great Faith dance. Stacey finds TJ and the two get in a fist-fight until Mr. Morrison arrives and breaks it up. He takes the Logan children home on his wagon and says that he won't tell their mother that they went to the store, but that it is up to them to tell their mother themselves.