A noun denoting active, effective power — not static potential but energy actually at work producing results. In the New Testament it appears almost exclusively in Paul's letters and refers overwhelmingly to divine power in operation. Paul speaks of 'the working of his mighty strength' that raised Christ from the dead (Eph 1:19), the 'energy' given to him for apostolic ministry (Eph 3:7; Col 1:29), and Christ's power 'that enables him to subject all things to himself' (Phil 3:21). The body of Christ grows through the 'working' of each individual part (Eph 4:16). Spanish 'energía' preserves the Greek etymological connection perfectly, while German 'Wirkung' ('effect, working') captures the emphasis on active operation rather than dormant capacity.