Overall, the Bible's usage conforms most closely to the Greek usage, that a prophet is one who speaks for another. As we will see, it is not limited to God. In this situation, Moses' and Aaron's relationship is analogous to God's and Moses'.
Moses is quite instructive in regard to our feelings about ourselves. We say, "What can I do? I'm so weak. I have no abilities." Moses said, "I am not a man of words." Was he not already justifying himself? He said, "I am heavy of mouth and tongue." (KJV) This is not exactly stammering, as some believe, but he is saying that he did not have a gift of speech. He means that he did not have it by nature, and that he did not have it developed within him since God began speaking to him. This is the same man about whom Stephen, who was defending himself against the Jews in Acts 7, said the following:
Is there a contradiction here? No, there is not. Both Moses and Stephen were correct. Moses was correct about himself. He did not have the gift of speaking, and he was not an eloquent man. Stephen was also correct. This is showing us that the power, the effectiveness in Moses' words was not in Moses himself but was in what God added to the words that came out of Moses' mouth. It was God who made the impact on the hearer's mind.
I would have to guess, to speculate, that in one sense this was never really overcome in Moses, that he was not eloquent as men would count eloquence. But yet what he said had awesome power because of God being in what he said. And so both men were correct—Moses about himself and Stephen seeing it from his perspective. Moses really said powerful things because God added to what Moses actually said. We have to remember this.
As you can see, in verse 14 God became angry at Moses' resistance, but really at Moses' unbelief is what it amounts to. God's promise to be with him did not mean that Moses would suddenly become eloquent and fluent. We have to understand that God knows how to use His creatures. He will use them to His end. If a man has great resources, his sufficiency makes God unnecessary, and he becomes puffed up. So God makes clear, through Paul, that He purposely calls the weak for His end.
This is what I mean when I said this is not limited to God and men, but also takes place from one man to another. Aaron was Moses' prophet, and Moses was God's prophet.
What is beginning to become clear here is that the prophet is a message-carrier from one of greater authority. In this case Moses was in the position of God to Aaron, and Moses thus was also in the position of God to Pharaoh.
By combining Exodus 4 with Exodus 7, the biblical usage of a prophet has a good foundation. It begins to become clear that a prophet is one who expresses the will of God in words, and sometimes with signs given to confirm what was said.
The difference between emotional immaturity and emotional maturity can be seen very clearly in the contrast between man's natural reaction to emotion (which is usually without self-control) and God's actions (which are always with control). Let us take a look at God's anger and His self-control. Even anger has its place in the arena of emotions. God always has righteous anger, but human beings most often have emotionally immature anger. And we are going to see the contrast to that. In Exodus 4, when Moses protested at the prospect of being God's spokesman before Pharaoh, although God was angry with him, He controlled His anger and came up with an alternate solution to this problem with Moses. God is speaking to Moses, and He says:
The emotion of anger is so powerful and destructive that it is expressed as the imagery of fire. Both humans and God are said to "burn with anger." As we see here, in verse 14, it says that the anger of the Lord was "kindled" against Moses—as if a fire is kindled. Anger might flare up like a flame, be stirred up like a fire, or smolder. Its similarity with fire is seen in its spontaneity, in its difficulty to be contained, and in its destructive power. So quite often throughout Scripture fire is used to represent anger and uncontrolled emotion.
God's anger differs from most examples of human anger. Expressions of God's anger exhibit no loss of control! Rather, as an act of God's will His anger results in deliberate judgments against sin—actions (1) appropriate to the situation and (2) in keeping with His own character as holy and just. God's anger does not have favorable outcomes for sinful, rebellious, complaining, and faithless people.
Moses was not really God, but in the teamwork here God is very clearly pointing out that Moses was the leader even though Aaron was going to be doing the bulk of the speaking, at least until Moses' confidence, his faith, got to the place that he didn't have to worry about being slow of speech. So Moses was in the position of the one issuing the orders. Aaron was in the position of submitting to what Moses said.
Moses was in the position of being God to Aaron, even as God was God to Moses, and Moses was God's prophet, but Aaron was Moses' prophet. A prophet is simply one who speaks for another (speaks the words that the other put into his mouth)—a very simple arrangement, easy to understand.
