Rashi: It is an end. Ibn Ezra #1 - the Nun is extra. Malbim - the Nun is in place of a second Tzadi. We find like this - "Lashmid Ma'uzneha", "Lo Samnu."

Ibn Ezra #2: It is many. There is nothing like this in Tanach.

Malbim: One who argues via intellect and proofs, he concludes the debate with the final deciding proof. One who argues via words without proofs, he wants to end the debate via words. He speaks until his opponent wearies ¹ . This is improper! First you should understand, and afterwards speak! Then, the debate will end via proofs of intellect!

Rashi: Be silent to understand what we say [before you speak]!