The secret signs and words allow the Gadiantons to come in among another people and operate for their own interests without visibly being the cause of the disruption. They could appear to be a peaceful part of the society while advocating and instigating major changes.
Even though Mormon will point to the north as their political connection, he continues his theme of noting that the worst enemies of the Nephites are apostate Nephites. These are more insidious that those he has previously mentioned, precisely because they hide their intentions.
The statement in verse 23, that they did their wickedness “contrary to the laws of their country and also to the laws of their God” speaks of the effects upon the Nephites. In verse 31 of this chapter we will see Mormon’s suggestion that the Gadiantons are from a very different religious tradition.