Alma is told to cry repentance to the Gideonites. Alma also urged repentance on the Zarahemlaites, but he clearly considered the people of Zarahemla to require a more drastic change than those of Gideon. Indeed, he has complimented the Gideonites and indicated that he will have joy in them – a joy that will not require that they make major changes first. How is it that they are being told to repent?
While the people of Gideon may not have been guilty of as great sins as those in Zarahemla, the call to repentance does not require great sins. It does not even require sins of commission. A call to repentance can come to any who are able to improve. Anyone less than perfect is in a position where repentance can usher a change, and improve the person. Thus the people of Gideon were good, yet still in a position where they might improve.
In this case, Alma is asking them to particularly prepare themselves to meet the Savior. This is no idle suggestion for something that is in the far future. The New World had the prophecies which marked the time of his coming, and Alma knows for certain that the day is approaching. These people are to literally to “prepare the way of the Lord.”