Why does it say "Karvu" and "Hagishu"?
Malbim: Karvu is refers to matters that are close to each other. Hagashah is a Katan in front of a Gadol, or something with much opposition, e.g. to approach to quarrel.
Does the verse tell them to quarrel?!
Rashi: They should come and debate with My children.
Radak: Yes. The verse addresses idolaters; it is a command to make their claim against Hashem and His nation. There should be a Dagesh in the Reish, just Reish cannot receive z Dagesh.
What are "Atzmoseichem"?
Rashi: Your healthy, strong claims. It is an expression of a quarrel in the Talmud - 'two who Nis'atzmu in a case' (Sanhedrin 31b).
Radak #1: They are Ta'anos Atzumos (awesome claims) that you have.
Radak #2: The Devarim ha'Atzumim (awesome matters) that you did in the world.
Malbim: Riv is a simple quarrel. Atzmoseichem is a quarrel in which the dispute gets stronger. There are nations that totally deny Hashem. They attribute the entire existence to chance, e.g. Apikoros. About this it says Rivchem, for it does not get stronger; most nations agree that a Creator made and formed everything. Only a few philosophers deny this. However, many deny "Melech Yakov", that Hashem chose Yisrael. This debate increased.
Why does it say "Melech Yakov"?
Malbim: This shows that he chose Yisrael to be His nation, and He is their king.