In ancient Greek, dunamis was potentiality, energeia was power in act. Agamben ( The Time That Remains: A Commentary on the Letter to the Romans ) thinks that Paul is perfectly aware of the distinction, and actually employs it in Ephesians 3:7 and Philippians 3:21.
Faith is the principle of actuality, as in “faith operative in love” (Galatians 5:6). For Agamben, the important point is that faith as the actuality of the power of God, is not external to the announcement of the gospel but is instead “That within it which makes potentiality active” (90). It is “the announcement’s [the gospel’s] being in act” (90). The gospel is not mere inert discourse, but the power of God in act as it is preached and received in faith. Thus it becomes the power of God from faith to faith.
