Two bits from my reading diet caught my eye:
“Nevertheless we still experience sin and death within us, wrestle with them and fight against them. You may tie a hog ever so well, but you cannot prevent it from grunting. Thus is is with the sins in our flesh,” (Complete Sermons of Martin Luther, vol. 1, 247).
“Precisely because the totality of the gift, the new being [the one justified by faith] knows that there is nothing to do to gain heaven. Thus the Christian is called to the tasks of daily life in this world, for the time being. Students, for instance, are sometimes very pious and idealistic about ‘doing something,’ and so get caught up in this or that movement ‘for good.’ It never seems to dawn on them that perhaps for the time being, at least, their calling is simply to be a good student! It is not particularly in acts of piety that we are sanctified, but in our call to live and act as Christians” (Gerald O. Forde, “The Lutheran View” in Christian Spirituality: Five Views of Sanctification, ed. Donald L. Alexander, 31).