Before Hannah Arendt coined the banality of evil in her study on the Eichmann case, there was Imam Ahmad ibn Hanbal.
During his detention his prison guard approached him. He asked Imam Ahmad if the hadith regarding those who assist the oppressors was authentic? Imam Ahmad replied in the affirmative and then was asked by the guard if he was one of those who helped the oppressors? This was ibn Hanbal’s response:
“No. The aides of the oppressors are those that comb your hair, and wash your clothes, and prepare your meals, and buy and sell from you. As for you, then you are one of the oppressors themselves!” 
Whenever you hear about individuals saying they are ‘just doing their job’ or that they are ‘trying to make a change from within’ – we should always ask questions about how the actions they take perpetrate injustices against others. Complicity is not always an active process, sometimes even well meaning behaviour can result in harm to others.
 ‘Manaqib al-Imam Ahmad’, by Ibn al-Jawzi, p. 397