Definition of CULLY: one easily tricked or imposed upon. A dupe. A foolish person SHEWED = "showed" or "has shown". I "think" (because I am not sure) that the Breach of Equity, refers to either a "disagreement" or an "unequal treatment" between the person and another. Somebody's "integrity" is in questioned or challenged by some comment. So he is saying that some previous remarks makes him feel that he should offer a similar remark, because without a response, he will appear like some sort of fool or dupe. Perhaps someone else can elaborate, because I am only generally confident as to my own understanding of this sentence.