This book uses the term “spokesperson” as a near equivalent to the biblical word “prophet”. Some may not like this.
But consider a few Biblical facts:
Who is the first person God recruited to be a prophet? Aaron.
Whose “prophet” was he? Not God’s, but his own little brother’s.
Why did his brother need a prophet? Because Moses claimed to be inadequate at speaking.
What did Aaron do as his brother’s prophet? He served as his brother’s spokesperson.
When the Lord called Jeremiah to be his prophet, what was Jeremiah’s response? “O Sovereign Lord, I can’t _______ for you.”
How was Jeremiah going to serve the Lord? Not by miracles, not by demonstrations of power, but by speaking. The Lord told him, “Look, I have put my words in your mouth.” Jer. 1:9. “Get up and prepare for action. Go out and tell them everything I tell you to say.” Jer. 1:17.
Prophets in the Bible served as spokespersons for the invisible, heaven-residing, eternal, living God.
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 Ok, Abraham was referred to as a prophet in Gen 20:7, these words were to a foreign king and include nothing about a call or assigned work.
 “… and your brother, Aaron, will be your prophet.” Exo. 7:1.
 “I can’t do it! I’m such a clumsy speaker!” Exo. 6:30.
 Jer. 1:6.