The ode Changdi in the Book of Songs praises brothers. “Of all the people of today, none are like brothers.” It also says: “Brothers quarrel within the wall, but they fend off insult from outside.” (兄弟阋于墙，外御其侮) The idiom xiongdi xiqiang, brothers quarreling at the wall, now means conflict within one’s own group.
A later stanza turns. “When the troubles are over and there is peace and quiet, though one has brothers, they are not as good as friends.”