Zerahemnah responds almost as expected. He does personally deliver up his weapons to Moroni, symbolically enacting the same for all of his troops. He accepts the opportunity to stop the war and leave. However, there is a caveat. “We will not suffer ourselves to take an oath unto you, which we know that we shall break.” As Zerahemnah also points out in verse 9, they do not adhere to the Nephite faith, and do not believe that it was God who won the battle, but rather the Nephites. Zerahemnah blames his defeat on the Nephite protective armor (verse 9).
The important point is that there was no similar religious belief between them that governed the taking of the oath, yet the very act of taking an oath was considered inviolable to both peoples. We encountered the ancient power of the oath when Zoram agreed to travel with Lehi’s family (in 1 Nephi 4) and was accepted upon an oath. The Anti-Nephi-Lehies took an oath, and suffered death rather than violate it. Zerahemnah is at least hinting that he is willing to do the same. The oath was more important to them than suffering death.