Dunhuang Scroll P.3899 was previously believed to be either a Buddhist scripture or a Daoist commentary, but was later determined by Kou Fengkai to be a transcription of a Daoist sermon, and is now seen as a valuable source of information on this topic. However, the interpretation of some passages and the dating of the redaction require further investigation. In an effort to further our understanding of this important Daoist work, in this paper I review the contents of the entire text and present the various opinions which have been put forth regarding both its interpretation and dating. In addition to presenting a list of all the tropes, metaphors, and allegories found in the text, I make an in-depth investigation of several of its stories and characters.