A religious discourse

One word substitute is Sermon.

Preach: deliver a sermon or religious address to an assembled group of people, typically in church.
Stanza: a group of lines forming the basic recurring metrical unit in a poem
Sanctorum: the part of a building or organization where few people are allowed to go, especially where the most important or secret work is done.
Sermon: a talk on a religious or moral subject, especially one given during a church service and based on a passage from the Bible.