Loyalty takes many forms in Sula. We see how parents display loyalty to their children by doing whatever is necessary to ensure their survival. We see friends who remain loyal to each other even when one hates the other. And we see failures of loyalty as men leave their wives, family members abandon each other, and best friends betray each other. Loyalty, or the lack of it, characterizes most of the relationships in the novel, and many of the complications and difficulties that arise stem from different ideas about what loyalty is.
Characters in the novel judge each other by their loyalty, or lack of it. They have no real interest in loyalty unless they feel they're not getting it.
Loyalty can be a powerful and beneficial force. It makes people consider someone other than themselves and creates important bonds.