She believed that she was an 'instrument' of God. [=she believed that God was using her to do things; she believed that God was acting through her]
Part of her training as a pilot involved learning to fly by 'instruments'. [=learning to fly only by looking at the instruments in the airplane]
Movies can be useful 'instruments' of social change. [=movies can be used to cause social change]
(..) And learn to read. Our first arrivals? For the greatest army ever assembled. And they will be our instruments. Our instruments of wrath. Are you really going to allow Lagertha to escape her punishment? No. We must have revenge. (..)2017 TvShow: Vikings Title: The Great Army Season: 4 Episode 17