This question is used to scold the brothers. Alternate translation: "You already know that this is the cup that my master uses for drinking and for fortune telling!" (See: [[rc://en/ta/man/translate/figs-rquestion]])
This repeats "you have done" for emphasis. Alternate translation: "What you have done is very evil" (See: [[rc://en/ta/man/translate/figs-parallelism]])