1. Joel 1:1 (ESV)
  2. Exposition

Why does Joel emphasize that he is passing on the word of the LORD?

Joel 1:1 (ESV)

1 The word of the LORD that came to Joel, the son of Pethuel:

All the emphasis is on the "word of the Lord." Often a prophetic book begins with historical notes (cf. Hosea 1:1, Amos 1:1, etc.). Joel calls attention to the authority of what he says. He is passing on words from God.