Northanger Abbey by Jane Austen Chapter 13 Page 23

Isabella should be doing wrong, felt greatly relieved by Mr. Allen's approbation of her own conduct, and truly rejoiced to be preserved by his advice from the danger of falling into such an error herself. Her escape from being one of the party to Clifton was now an escape indeed; for what would the Tilneys have thought of her, if she had broken her promise to them in order to do what was wrong in itself, if she had been guilty of one breach of propriety, only to enable her to be guilty of another?