The Iron Circle explanation

"Iron" = the state of being in an Ironform. By having the entire 4th Officio community have Ironforms, that will create...
"Faith" = the communal bonds forged between each 4th Officio Magical Girl. From this bond of unity, the 4th will gain...
"Strength" = individual might, both physical and mental. That will give them...
"Will" = the mental fortitude to endure hardship and improve oneself. From this quest of self-improvement you get...
"Knowledge" = scientific knowledge, and the engineering knowledge required to apply it. By mastering the machine, the Fourth Officio can better make themselves into...
"Iron": and so the cycle begins anew.