In a comment on Colossians 3.7 (“In these too you once walked, when you were living in them” [ESV]), John Calvin makes use of the distinction between actus and potentia to explain the difference between “walking” and “living” in the verse (after having a little dig at Erasmus for what Calvin considers exegetical malfeasance):
Erasmus [did] poorly, who referred [these words] to men, translating “Among whom.” For Paul doubtless understood [them to be] about vices, with which he says the Colossians were occupied at the time at which they were living in them. For “to live” and “to walk” differ between themselves as potency and act: to live precedes, to walk follows. Galatians 5.25: “If you live by the Spirit, also walk by the Spirit.”
For Calvin, these categories were useful for the interpretation of Scripture, which is to say, for glossing Paul’s own more concrete categories. Just as potency precedes act in non-divine creatures, so must life form the backdrop against which and environment in which conduct of life occurs. Living apart from the Spirit of Christ is the deep background of walking in vice, whereas living by the Spirit of Christ is the deep background of walking by the Spirit.1
- I was pointed to this passage by T.K. Abbot’s commentary on Colossians. The translation is my own.