Alma concludes his sermon with yet another plea for the people of Ammonihah to humble themselves and repent. In the case of Ammonihah, it was particularly important that they “not procrastinate the day of [their] repentance.” There was a prophesied destruction coming, and it was not far in the future.
The promise made to them is the same promise to us all. Through the Atonement, the Lord may grant us repentance, and through repentance we will not need to suffer the second death.