What is the meaning of "Ehi Malkech Efo"?
Rashi citing Targum Yonasan: Where is your king?
Rashi: I will stand opposite, to see where is your king. I will see your end - where your savior is.
Radak: I will exist forever, but your king - where is he? You despised My kingship, and requested a king who will save you - "v'Yatza Lefaneinu v'Nilcham Es Milchamoseinu" (Shmuel I, 8:20). Where is he who will save you?
Targum Yonasan: Where is your king? Radak - he explains Ehi with the last two letters reversed (Aye).
Malbim: Your ruin is because you have no king. You rebelled against Hoshe'a ben Elah and slandered him to Melech Ashur. Via this, you were ruined. Will I be your king to protect you from Melech Ashur?!
Why does it say "b'Chol Arecha"?
Radak: Enemies come against you in all your cities.
Malbim: Search in all your cities and all your judges - where is your king who will save you?
What does the verse teach about "Shofetecha"?
Radak: You willingly put them upon you. You see that the king, executives and officers help you only with My help!
Why did they say "Tenah Li Melech v'Sarim"?
Malbim: In the days of the Shoftim, Hashem was their king. He saved them, like in the days of Shmuel. Then they gathered and requested a king, for they despised Malchus Shamayim; Shmuel criticized them for this. Hashem told him "Lo Osecha Ma'asu Ki Osi Ma'asu mi'Meloch Aleihem" (Shmuel I, 8:7). Initially they were under Hashem's Hashgachah, above nature. They requested to conduct based on nature. If so, how do you request now that I will be your king? You despised My kingship, and chose a king to save you via war!