Why is Mrs. Frank's statement of "he steals once, he'll steal again!" an example of irony?

The statement is an irony because the food that Mrs. Frank accused Mr. Van Daan of stealing wasn't even theirs too.

Explanation:

In The Diary of A Young Girl, Anne Frank records her and her family's life during their hiding period from the Gestapo. This diary became one of the most famous witness records of the Holocaust under the German Nazi regime.

The irony in question is when Mrs. Frank declares "He steals once, he'll steal again" which is directed to Mr. Van Daan. The Van Daans have also come to stay in the Annex to hide with the Franks. And Mr. Van Daan had stolen food that has been kept for everyone but which they had to consume sparingly, for they are in hiding. And the irony is that the food that she said he stole wasn't even theirs.