Alma has a dual reference here. Clearly he is invoking the seminal experience among the Zoramites. He has already noted that it was a watershed experience for Shiblon, and now he refers to that experience to hammer home the gospel lesson he is teaching. He also reiterates the point about humility, and not boasting in one’s own strength by using this specific example of a people whose religious rebellion stemmed from precisely such self-pride and self-aggrandizement.