Even though the people of Ammonihah are in apostasy from the Nephite religion, Alma treats them as Nephites, and, therefore, inheritors of the blessings that have come to the whole of the Nephite nation. Thus, they have “been favored above every other nation, kindred, tongue, or people.” Although the people of Ammonihah certainly believed that this favor described their own city, it will be clear as Alma continues that he is speaking of the Nephites in general, rather than the people of Ammonihah specifically.
It is as Nephites that they have been taught “that which has been, and which is, and which is to come.” This phrase is intended to describe the gospel. The Nephites were taught that which was, because they have been taught of the prophets and prophecies from the brass plates. They are taught that which is, because the Nephite church continues those teachings and preaches them. They are taught of that which is to come, because they have been taught about the coming atoning Messiah.