What does Jeremiah 49:12 mean?

This is what the Lord says: If those who don’t deserve to drink the cup have to drink it, shouldn’t you drink it too? You won’t go unpunished. You’ll have to drink it all. Jeremiah 49:12 - Modern Text Bible

(If even the innocent have suffered, Edom certainly won’t escape punishment. The ‘cup’ is a symbol of God’s wrath.)