Alma’s baptism became the sign of entering into a church, which was being organized on the spot. Since the Limhites’ understanding of religion at that point consisted of the obviously apostate version of Noah and the obviously Yahweh-approved church of Alma, naturally the Limhites wanted to follow Alma’s example in becoming a church. There is no clear indication that a church existed in Zarahemla at this time. The first mention occurs in Mosiah 25:18–19 after Alma’s arrival and ministry in Zarahemla. It seems likely to me that Ammon is balking, not over the smaller issue of authority to baptize, but rather at the greater authority of forming a church. Being asked to perform a baptism in the context of creating a church would have been unfamiliar territory and a place where Ammon declined to go without more specific instruction from King Mosiah. Otherwise, if Ammon had the priesthood and the authority to baptize, it is hard to imagine why he would deny the ordinance to a people who were so clearly prepared for and desirous of it.