Yahweh asks this question to make the people of Judah think about what they were saying. It can be translated as a statement. Alternate translation: "You think that you are wise because you have the law of Yahweh with you." (See: [[rc://en/ta/man/translate/figs-rquestion]])
The pen represents the words that the scribes write. Alternate translation: "The false things that the scribes write" (See: [[rc://en/ta/man/translate/figs-metonymy]])