Why is He called "Melech Yisrael v'Go'alo"?
Radak: When He will redeem us, He alone will be Melech Yisrael. Yisrael will not be in the Reshus of Nochri kings. He is the Master of legions above and below, and everything is in His ability, to take them out of Galus.
Why does it say "Ani Rishon va'Ani Acharon"?
Radak: I am first even to the legions above, who do not change; I created them. I am last - they will cease, and I last.
Malbim: He refutes those Nochrim who denied that Hashem is Kadmon (always existed).
What do we learn from "umi'Bil'adai Ein Elokim"?
Radak: This refutes the belief of those who serve the sun, moon and stars. Not one of them is Elokim; what they conduct is due to My command and permission.
Malbim: He refutes those Nochrim who denied Hashem's unity.
