The command from the Lord to warn a city of imminent destruction is reminiscent of the story of Jonah’s call to Nineveh (see particularly Jonah 3). There are, however, rather significant differences, in that Alma is hardly hesitant as was Jonah, and Nineveh repented and avoided destruction, where Ammonihah will not be so fortunate. Nevertheless, the similarity is instructive for the care the Lord takes to warn those who are his children of what they need to do.
While the cases of Nineveh and Ammonihah are for entire cities, the important aspect for modern readers is that the call was to repent. In both cases there was destruction on the horizon, and the preventive measure was not great fortifications in masonry, but rather in the fleshy tablets of the heart. The defense was not military, but spiritual. Each community was called to repentance, and the heed given to that call in Nineveh had the desired effect and averted the potential disaster.