walls is a form of:

Sermon



noun
1.
(A talk on a religious or moral subject, a speech any serious talk on one's behavior, responsibilities etc) ការបង្រៀនដោយស្និទ្ធស្នាល (សាសនា), ធម្មទេសនា, ទេសន៍
Example: When his report card arrived, the boy got a sermon from his father on the meaning of hard work.
Example: A book of sermon.
2.
(បច្ចេកទេស) ធម្មទេសនា, ការក្រើនរម្លឹក
ENGLISH MEANING
noun
1.
A discourse or address; a talk; a writing; as, the sermons of Chaucer.
2.
Specifically, a discourse delivered in public, usually by a clergyman, for the purpose of religious instruction and grounded on some text or passage of Scripture.
3.
Hence, a serious address; a lecture on one's conduct or duty; an exhortation or reproof; a homily; -- often in a depreciatory sense.
verb
1.
(INTRANSITIVE) To speak; to discourse; to compose or deliver a sermon.
2.
(TRANSITIVE) To discourse to or of, as in a sermon.
1.
discourse, guide, homily, lecture, message, oration, speech, talk
1.
To tutor, to lecture