Jesus is using this question mainly to rebuke the Jewish leaders for not listening to him. Alternate translation: "I will tell you why you do not understand what I say!" (See: [[rc://en/ta/man/translate/figs-rquestion]])
Here "words" is a metonym for the "teachings" of Jesus. Alternate translation: "It is because you will not accept my teachings. (See: [[rc://en/ta/man/translate/figs-metonymy]])