What is the question "Mah Hi"?
Rashi: What is leaving, that you told me to see it?
What is the meaning of "Zos ha'Eifah"?
Rashi: You will see [leaving] like a Kli used to measure an Eifah.
Radak: These are the 10 tribes that were already exiled. They are sunk in Galus. They did not leave Galus now, like Yehudah and Binyamin. This was Midah k'Neged Midah - just like they did evil for a long time, from when the kingdom was split until they were exiled, they did not have one king who persisted 1 to do good. Rather, all of them went in an evil path. Just like they did evil many days, their Galus extended many days. An Eifah (measure) hints to Midah k'Neged Midah.
Malbim: This is the measure that goes out to judge Midah k'Neged Midah. The punishment is like the measure of the sin. This Eifah that goes out to punish for other sins, it does not leave the Heichal, like the Megilah did. Other sins do not go in front of the Mizbe'ach like false oaths do.
He uses this expression due to Yehu, who initially was a Tzadik, but later soured. (PF)
What is the meaning of "Zos Einam b'Chol ha'Aretz"?
Rashi: This is the measure with which were stricken those whose eyes are in the entire land to steal, oppress, decrease the Eifah (measure of grain that they sell) and increase the Shekel [the coins that they take]. They were punished measure for measure!
Radak: This Eifah that you see, it shows that there is an eye on them that sees their deeds. [Hashem] sees in the entire land - "Einei Hashem Hemah Meshotetim b'Chol ha'Aretz" (4:10). "Einam" - the eye that sees them, it is Hashem's eye.
Malbim: The eye that oversees these sins, it is not the eye in the Heichal. Rather, it is the eye and Hashgachah that is found in the entire land to punish according to the sin. It is not as severe as the eye in the Heichal.
