TITLE. The word of the LORD. Therefore not Joel's. This is the Divine key to the book Joel's pen, but not Joel's words, Compare Act_1:16 for a similar fact concerning David.
the LORD. Hebrew. Jehovah. App-4.
Joel = Jehovah [is] GOD.
the son of Pethuel. This does not imply that Pethuel was a prophet. It merely distinguishes this Joel from others of the same name.