What is the tense of "Lako'ach"?
Radak: It is Makor (infinitive) in place of a command, like "Haloch v'Karasa" (Yirmeyah 2:2).
What is "me'Es ha'Golah"?
Radak: From those who came from Golah - Cheldai, Toviyah and Yoshiyah.
When is "ba'Yom ha'Hu"?
Radak: When you will come there. He was not told to go there on the day of the Nevu'ah.
Why should he go to the house of Yoshiyah?
Radak: The others were in his house.
Malbim: Hashem commanded him not to wait for them to come to him. Rather, the Navi should go to them immediately. They gathered in Yoshiyah's house when they came from Bavel.
To whom does "Asher Ba'u mi'Bavel" apply?
Rashi: It applies to all these people.