I’ve argued that Jeremiah was a prophet like Moses, and Jesus is the typological fulfillment of this pattern that began with Moses. Luke presents both Peter and Stephen asserting that Jesus is the prophet like Moses announced in Deuteronomy 18:15–18 (Acts 3:22–23; 7:37), and Matthew, Mark, and Luke are pointing to this in their transfiguration accounts (see esp. Luke 9:31, 35).
The Lord told Moses that he would be “as God” to Pharaoh with Aaron as his mouth (Exod 4:16). It’s as though Moses represents God and Aaron becomes the prophet of God.
Moses spoke for God. One aspect of being a prophet like Moses, then, is speaking for God.
In Jeremiah 4:19–22, Jeremiah is speaking in the first person (“My,” “I”, etc.). It seems that Jeremiah is speaking of himself in verse 19, “My anguish, my anguish! I writhe in pain!” And he continues to speak in the first person through verse 26. By 4:22, though, it appears that he is speaking as or for Yahweh rather than himself when he says, “my people are foolish; they know me not; they are stupid children; they have no understanding.”
The key phrase here that makes me think that the “I/My” is Yahweh rather than Jeremiah is “they know me not” (Jer 4:22). It seems that the problem the people have is that they don’t know God. Even if this is merely Jeremiah saying that the people don’t recognize him as Yahweh’s prophet, the cause of that would that they don’t know God, so it still points to Jeremiah speaking for God.
It seems to me, though, that what’s in view is not that the people don’t know Jeremiah (though they are not heeding his message). The problem is that they don’t know God. So in Jeremiah 4:19–22, it seems that Jeremiah begins speaking of himself in the first person and ends by speaking for Yahweh in the first person.
I take this as another way that Jeremiah is a prophet like Moses. God made Moses to be as God to Pharaoh (Exod 4:16), and God made Jeremiah to speak for God to the people of Israel.
This trajectory will be fulfilled in the one who came as God incarnate and spoke as God to the people. Jeremiah, then, is an installment in the typological pattern of the prophet like Moses who speaks for God, a typological pattern that Jesus fulfills.
If you want more on this passage, here’s my sermon on Jeremiah 4:5–31, “Wash Your Heart from Evil.”