The people were to actively seek instruction from the priests. Just as books in a library, safeguarded by the librarian, will do not good as long as they merely sit on the shelves in the library, so the knowledge safeguarded by the priests will do no good if that knowledge is not put to use. Just as patrons of a library need to read the books to benefit from the knowledge contained in them, so the people of God must seek instruction from the priests safeguarded by them.
7 For the lips of a priest should guard knowledge, and people should seek instruction from his mouth, for he is the messenger of the LORD of hosts.