It does make sense, contextually. Kind of.
Elidibus is the first ever in-universe "Warrior of Light," having acted as a hero at times to counterbalance the other Ascians' dark and chaotic influence. Thus by putting their faith in the concept of "Warriors of Light," people are unknowingly putting their faith in him.
So by believing in Warriors of Light, people are believing in Elidibus, which gives him power.