Alma got a cold reception and brusque rejection among the Ammonihahites. They said, in essence, Who do you think you are? We are not going to listen to you even if you were to “prophesy that this great city should be destroyed in one day”—which is literally what happened (Alma 16:1–11).
On their belligerent attitude (“Who is God?”), see commentary at Mosiah 11:27, 29.