Chapter 1: Yirmiyahu is appointed as a prophet

1. His background:

His name and lineage: Yirmiyahu was the son of Chilkiyahu. He was a priest.
His place of dwelling: He lived in the city of priests known as Anasos, which was located in the land of Binyamon.
The era of his prophecy: Jeremiah prophesies in the days of Yoshiyahu the son of Amon who was the king of Judah. The prophecy took place in the 13^th year of his reign. His prophecies lasted throughout the reign of Yehoyakim the son of Yoshiyahu who was the king of Judah, up until the 11^th year of reign of Chizkiyahu the son of Yoshiyahu the king of Judah. He prophesied until the citizens of Jerusalem were exiled in the fifth month.

An appointment from the womb: God spoke to Jeremiah and said to him, prior to you being formed in your mother’s womb I have already made Myself known to you, and prior to leaving your mother’s womb I have sanctified you, as I have appointed you as a prophet for the nations [i.e. the Jewish people who are acting like the idolatrous nations[1]].
The initial rejection: At first, Jeremiah rejected the appointment of becoming a prophet stating that he is a mere lad, [and is incomparable to Moses who performed many miracles and merited to lead the Jewish people[2]]. God however rejected his claim of invalidation due to being a young lad and instructed Jeremiah to follow through with all of the messages and instructions that he is given [on behalf of the Jewish people and Gentile nations[3]].
God touches the mouth of Jeremiah: God then sent his hand and touched the mouth of Jeremiah and told Jeremiah that he has now placed His words on his mouth and has now appointed him over the nations and kingdoms to destroy and eradicate, and to build and plant.

The word of God came to Jeremiah and asked him; What do you see Jeremiah? And Jeremiah replied that he sees the staff of an almond tree. God replied to him, you have seen well, as I am vigilant to perform the prophecy in the very near future.

The word of God came to Jeremiah and asked him; What do you see Jeremiah? And Jeremiah replied that he sees a boiling pot which is boiling towards the north.
A prophecy of the conquering of Israel and destruction of the temple: God responded to Jeremiah stating that this prophecy is a hint that from the north will open the evil upon all the residents of the land of Israel. As I will call upon the nations which dwell to the north of Israel to lay siege to the gates and walls of Jerusalem and to all the cities of Judea. All this is in retribution for the evil that the Jewish people have done to Me that they have forsaken Me and offered incense for other deities and prostrated towards their idols.
A promise to Jeremiah that he will remain safe upon saying his prophecy: Now, Jeremiah gird your loins and get up and speak to the Jewish people that which I have told you to tell them. Do not fear them as if you do fear them, then you will get injured before they. I have appointed you today like a strong fortified city and like a pillar of fire and wall of copper against all those who desire to harm you, including kings and ministers who will unsuccessfully try to fight against you, to stop you from saying the prophecy, as I will be with you.

[1] Rashi 1:5

[2] Rashi 1:6

[3] Rashi 1:7