1) Jeremiah was called by God to be a prophet to the nations even before he was born. God sanctified him in the womb and ordained him as a prophet.
2) When directly called by God around the age of 18-20, Jeremiah doubted his ability to speak to the people because of his youth. However, God reassured Jeremiah that He would give him the words to speak and make him strong like a fortified city against opposition.
3) God showed Jeremiah visions of an almond tree branch and a boiling pot to symbolize that God's word would certainly be fulfilled through the coming destruction of Judah by Babylon from the north, represented by the boiling pot facing