Sociological: We have in this verse a very similar historical event to that referred to in Acts 11:25: "26 …And the disciples were called Christians first in Antioch." In the Old World, the earliest designation of the followers of Christ was "The Way" (Brown, Raymond E. An Introduction to the New Testament. Doubleday, 1997, p. 81). Paul clearly uses this term to denote the gospel before Felix:
"However, I admit that I worship the God of our fathers, as a follower of the Way, which they call a sect…" (Acts 24:14, New International Version).
The shift from "the Way" to "Christians" signaled not only an internal/external designation, but a recognition of a more formalized structure to those who followed "the Way," or those who were "Christians." Horsley and Silberman note:
Just as a shift in terminology in the old world formalized the outward perception of the Christian community into a "church," so with Alma is there a creation of a new entity. In this case it is very specifically the "church of God," or "the church of Christ." We must also understand this new designation, as the word typically translated "church" in the New Testament is the Greek ekklesia, and that Greek term could not be the word that Mormon wrote on the plates. Indeed, some have suggested that the mere presence of the concept of "church" prior to the time of Christ is an anachronism. What is it doing here in the Book of Mormon?
Jeff Lindsay writes:
"…we read of Alma establishing a church in the land nearly a century before the birth of Christ, and some critics feel this represents a major blunder in the Book of Mormon. But the concept of a church - a convocation of believers - was had among the House of Israel prior to the coming of Christ. I quote from the outstanding Bible scholar, Alfred Edersheim, who is not LDS, as he discusses the meaning of Christ's statement to Peter about building His church (Matt. 16:15-18):
As one of many examples, Psalms 89 speaks of praising the Lord "in the congregation of the saints" (v. 5) and says that God is to be feared (respected, revered) "in the assembly of the saints." Why not call such a congregation or assembly of worshipful believers a church? In fact, the Septuagint does, using the Greek word "ecclesia" which is translated as "church" when it occurs in the King James Version of the New Testament."(Lindsay, Jeff. http://www.jefflindsay.com/LDSFAQ/FQ_BMProblems.shtml#church).
Any argument based upon specific words in the Book of Mormon, such as church ignore the problems of translation. We do not know what the original word was that Mormon wrote. We know only that Joseph Smith translated that word as "church." In modern terms, "church" means as much a specific organization as it does anything else. There is a sense of that in Alma. As has been noted before, religion and life in the ancient world were inextricably intertwined. The conception of belonging to a religion was foreign to most of the ancient world. Religion provided their definition of reality, it was their science, and their definition of the way the world worked. Particularly in smaller communities, everyone would have the same world view, the same religion. What we see happening with Alma is the formalization of a particular type of belief, the understanding that the Mosaic laws must be seen in the light of a coming atoning Messiah. That community of believers separated from their larger community, and in that separation created a subset of society. They were a people sharing the same language and material culture, but no longer the same set of beliefs about how the world worked. As a separated community with a covenant of entry (baptism) they fit the definition of "church" regardless of the way we might read the word or surmise the underlying "Nephite" word.
Alma's community is created from very specific social pressures. The response to those pressures was to create a religio-political structure that could define his new community both as its own entity and in opposition to the greater culture from which it was derived. While the earliest existence of this community was as a separate town, when it is integrated into Zarahemla society, it brings with it the ability to define a subset of a community that is defined by religion rather than economic status. This is an important distinction that was probably not available in most Mesoamerican communities at the time. King Benjamin's speech instituting social reform in Zarahemla followed a time of social unrest and the removal of the dissenters to the Lamanites. In Benjamin's case, there was no mechanism for establishing internal divisions that could remain separate, yet part of the community. It is precisely this conception of a separate entity that might exist within a community that Alma creates as his religious innovation, an innovation that he will take with him and institute formally in Zarahemla. As we will see in that setting, it allows for the continuation of the body of believers amidst a larger cultural setting that does not always uniformly adhere to those beliefs, even though there may be a political tie to Zarahemla.