Both of these phrases mean that their punishment is the result of their wicked behavior. Alternate translation: "Because you have been wicked and unfaithful, I will punish you" (See: [[rc://en/ta/man/translate/figs-personification]] and [[rc://en/ta/man/translate/figs-parallelism]])
Here the word "bitter" describes "wicked." Alternate translation: "it is bitterly wicked" or "it is extremely wicked" (See: [[rc://en/ta/man/translate/figs-hendiadys]])